Fallingwater

My main ride is a Raleigh Cadent FT0 with its original Shimano Altus derailer.

A while ago the bike was vandalised and the derailer and hanger were both bent. A LBS replaced the hanger and unbent the derailer, but warned me that there was now play in its movement from the damage it had sustained and it would shift badly - which is indeed the case.

I've finally grown tired of all the shifting troubles I've been having since that day and decided to replace the derailer with a new one. I can get an Altus RD-M310DL on Amazon (which looks exactly like the one the bike currently has) for €14. I can also get an Acera RD-M360 for €21. The price difference is not large and according to what I'm reading Acera stuff is one rung upward from Altus in the quality department. Realistically, would I notice any difference between the new (and properly working) Altus and the Acera?

Also, is there any difference between the Altus RD-M310 and the M310DL? I can't find the non-DL on my local Amazon and most other stores can't seem to make up their mind over which model they have (is there even any difference at all?).

hermanchauw

They all work.

Fallingwater

I'm aware. What I'm trying to figure out is if the Acera works perceptively better.

alcjphil

Brand new, you might not notice much difference, but the Acera might prove better and more durable a few years down the line. Probably worth the small difference in price

Andrew R Stewart 

The big point of difference between adjacent models in Shimano's line up is, IMO, between the Tourney and the Altus. Basic construction, pulley and design are rather different. But between the Altus and the Acera these are fairly minor, some material and finish but the basic design remains. Having said that I have rarely experienced a customer who decided to "up grade" and later regretted it. Andy

djb

We've had, and have, bikes with various generations of both, and all work perfectly well when drivetrain maintenance is done regularly.
As mentioned, one step up is generally slightly better materials, so worth the small extra money if you plan to ride and keep the bike over the years.

Retro Grouch 

How thin can you slice the baloney? At what point does a rainbow change from red to orange?

Shimano makes bicycle components in so many price ranges that I can't keep track of them all. The high end ones really are nicer than the cheapies. They make so many variations, however, that nobody I know can tell one from the next functionally if they go up or down only one component group.

Price is another matter. Performance improvement is pretty much a straight line. The price increase line is exponential. Everybody has a different idea of where the performance improvement isn't worth the price increase anymore.

Bill Kapaun

As you go up the food chain, DER's are designed for "more speeds", resulting in narrower cages.
Stick with a DER designed for the #speeds you have.
Did you ever have problems with your current RDER before the vandalism?