I was between the Checkpoint SL5, ALR5, and the Revolt Advanced 2. There are no bad choices here. The shop was a minor factor, though I did end up buy the Revolt at the local shop that sponsors my bike club, so while that wasn't the reason I bought it there, it's a nice plus.
I have a 2013 Trek Domane with Isospeed in the rear and it is wonderful. It works and definitely smooths out the road - for me the difference between the front and rear of the bike is pronounced. The Checkpoint felt very familiar - smooth and similar - though a tad slower. It is a handsome bike too. I liked it.
To me, the Revolt felt more playful. It is also very smooth. Instead of relying on a decoupler, it relies on a flexing seat post and handlebar, and it really works (the tires help a lot, of course). I've only recently noticed how good the handlebar is at smoothing the road, because it is much better at this in the drops than at the hood.
I test rode the aluminum Revolt and the Revolt Advanced 0 and bought the RA 2, because I didn't feel the need to go above 105. I've had some issues, mostly probably due to a sloppy built at the shop. The most notable is that the seat post slipped all the time to the point that the bike was unridable. Eventually a swap for a new post solved that issue. The other thing I'd say is that the wheels are HEAVY AF and really takes work to get them spinning. The RA 0 has carbon wheels for $1100 more - that is a good move. I'm replacing my stock wheels as soon as I can for lighter alloy ones and putting wide tires on the stock for days that are more single-track than gravel.
These are two excellent bikes. I bought the Giant in part because it is my
#2 "road" bike. If it was buying a Swiss Army knife bike, it would be the Checkpoint. I think it would be better on the road with faster tires.