Used 7700 STI or Sensa/Microshift
 

I'm venturing back into large and fast group rides and considering going back to STI on my go fast bike. It's currently 7700 DT shifting.
Two questions:

How would I inspect a CL set of levers and what are the danger signs?

If you have experience with 7700 or 6500 levers, how do the Sennsa and Microshift levers compare regarding solid dependable and durable mechanisms?

I wouldn't bother with used shifters. You can't really tell if they work well unless they are cabled. You may be able to find NOS on ebay but it will be pricey. I wouldn't hesitate to use Microshift. I've read that 11 speed Campy is another way to shift 9 speed Shimano.

I really like the Microshift brifters. The separate upshift and downshift paddles fall under my fingers just right.

Top

Cut about a ten inch piece of cable with head. 7700 sti is pretty smooth so it shouldn't hang up at all. Run it up and down to make sure you get 8 clicks and try it again with the cable in place. The head should drop easily into the seat.

Just make sure the hoods are not ragged or torn. 9 speed Shimano brifter hoods are unobtainium at this point.
Microshifts are good too. I put Microshift R9 short-reach 2x9 brifters on both my kids' bikes. They feel very solid and shift with a nice loud clack. One other good thing is that the R9 comes in silver color as well, which goes well with classic bikes.

Shimano Brifters from 8 spd up, 105 and up, my experience is that they are bulletproof and will last 'forever'.
Only caveat I've found is 'crash damage' - may make them unusable... Otherwise, they do get dirty/gritty with age.
I've taken 6 sets of Brifters from 105 to dura ace, which were not functioning properly and cleaned them extensively, using WD 40 sprayed on the innards.
4 sets I bought for cheap - 8-9-10 spd , 105, ultegra and dura ace, which were not shifting proper or not holding the shift.. They're all still on bikes and have had thousands of additional miles... other two belonged to friends, one Ultegra 6700 - recently sold on bike, but ridden hard before and functioning flawlessly prior to sale. The Other, Dura ace ST7900, rough cosmetic condition, crashed a couple times, but still functioning with no concerns... all cable systems - can't speak for electronic...
might cost you a can of WD40...
I have a brand new pr of Microshift R9 shifters, which I've yet to put on a bike... hoping to get around to it finally this year... wanna see how they work...
ride on
Yuri
EDIT: actually I'm not sure which model microshift they are - in a box somewhere in my bike parts... I'm fairly certain they are 10 spd... need to find them... maybe this wkend... LOL!

I'd second the advice not to get used 7700, the right hand shifter had a habit of only shifting 5 of the 9 gears once they wore out. I've still got 2 sets of Ultegra 9 speed shifters that are working fine but once the hoods are gone they're nt possible to replace. Honestly right now I'd be looking at 10 speed shifters, they will still be compatible with your derailleurs and chuck a new cassette on. The ten speed stuff with external cables is much more robust than the 9spd DA especially and hoods are currently available new if you'd like to slug away a couple of sets. I've had hands on the microshift and sunrace shifters, and personally prefer the shape and build quality of Shimano.

I have serviced old Sora to 1st Gen Dura Ace Brifters.
They were all sticky and slow to shift.
Simple fix.
Get a can of Brake Cleaner fluid
Blast it into the mechanism a few times followed by compressed air.
Lube with Light oil. Voila. Worshing shifters

Don't want to beat a dead horse here, but the issue with 7700 shifters was mechanical, the pawls would wear/break off and it couldn't be repaired by flushing and re-lubing. It also wasn't every set that would do it, but maybe one in five or one in ten, enough to make buying a used set a bit more risky than other generations.

I'd probably go microshift unless having exposed cables bothers you, then spend more for Campy11.

I've used MicroShift R7 7-speed brifters for a couple of years, no problems. They aren't as elegant as the Dura Ace 8-speed brifters (the only others I've tried), and shifting sounds a bit clacky, but MicroShifts are great values.

The hoods and covers are very comfortable. MicroShift uses separate paddles for shifting up and down, and the brake levers only brake, so operation is pretty straightforward. Braking is very smooth with excellent leverage, better than my older Suntour GPX, Shimano 600 and other aero brake levers.

The only time I notice the exposed cables running inward, roughly parallel with the handlebar, is when I'm using a headlight. I've used elastic hair bands, tape or zip ties to gently pull the cables into a better position so they don't reflect my headlights or interfere with my bike computer, video camera mounts, etc. (I run video front and rear every ride, especially after being hit by a car a few years ago.) A few weeks ago I moved my camera mount under the handlebar/stem to declutter the top. I neglected to be sure steering both extremes wouldn't interfere. Sure nuff, a mile from home I heard my front camera tumble onto the road. The crossing cables pressed the spring-operated quick release and detached the camera. Fortunately the camera was fine, just a couple of scuffs (Drift Ghost X and similar Drift models are really rugged). I used an elastic hair band from my ponytail to reorient the cables slightly, no problems since. So that's the only issue I've had with cables, but it's the same with all my bikes with exposed cables, including my hybrid with bar end shifters and those large cable loops under the bars and grips. There's always a bit of a trick to arranging the cables to avoid interfering with the other junk I clutter up my bikes with.

Beware when searching for MicroShift -- MicroNew will often pop up instead. Those appear to be similar or identical, but user reviews indicate MicroNew may be of lesser quality. I suspect Amazon and possibly Google are pushing MicroNew in searches because MicroShift have been in short supply since the pandemic and economic related shortages and supply chain issues.

I like the MicroShift brifters well enough I may get a set in 10-speed. I cannibalized a 10-speed group from an old tri-bike, but it came only with Dura Ace 10-speed bar end shifters. If I can be sure the MicroShift 10-speed brifters are compatible with my 10-speed DA rear derailleur and cassette, that'll do just fine. Otherwise it'll be cheaper to buy an Ultegra or 105 rear derailleur in 10-speed than find good working 10-speed Dura Ace brifters.

If I had to pick new between Microshift and Sensah, if money was less of a concern, Microshift all the way.
I have both a set of MS 10 speed brifters on one bike, and 11 speed Sensah groupset on another. My microshift, as clunky sounding as the shifts are, they always work. I've had troubles with my left Sensah shifter. Sometimes after shiftiing to the larger chainring, I have the give my left shifter a tug to the left to get it engaged to shift to the smaller chainring. I never have that problem with any of my Microshift groupsets.

I've had so many 7700 STI failures, I've lost count. On my own bikes, I've gone with nine speed Microshift instead. I've had similar problems with the 6500 STIs. I either go 8 speed (6400 and 7400), or Microshift.