Originally Posted by
Menel
Acera is a mtn groupset.
It changes with generation to generation, so some of this may not be current. But for Shimano road groupsets it's something like this from cheapest to most expensive.
Sora: Cheap. Lots of plastic bits and what is metal, isn't plated so low durability and low protection from corrosion. Works well enough but missing features such as trim.
Tiagra: Similar to Sora, but loses the thumb shift lever for improved ergonomics.
105: More reliance on metal parts. Durable, e.g. outer chain plates are now nickel plated for corrosion resistance. Trickle down features from the latest DuraAce technology. Has pretty much the latest or one gen behind on hyperglide chain/sprocket cuts, and trim in both directions for shifting performance.
Ultegra: Lighter weight. Smoother operation. Most durable, e.g. both inner and other plates of chain is nickel plated for corrosion resistance, and other bits throughout groupset. More premium metals and materials like carbon shift levers.
DuraAce: Lightest. Smoothest. Sacrifices durability for weight, e.g. cassette uses titanium which wears faster than the hardened and plated steel of Ultegra.
Sora is cheap, but the low durability bit is questionable. My Sora has been great for 4 years now, and requires no adjustments. Even has been through 3 spills, no problem. Doesn't shift as crisply as 105-DA, but I disagree with that it's low durability. No corrosion whatsoever on mine, but I also don't ride it in the rain. (I do sweat a lot though.)
The thumb button is an issue for some - some like myself don't mind it at all, but it does make it impossible to hit that button in the drops - you have to get on the hoods.
I don't doubt the cold-forget DA will have much greater durability than Sora, but I think we've already passed the point where even the least durable of the groupsets last so long that you have to willingly break or abuse them to damage them.
I heard so much crap about how crappy Sora was and how quickly it would break, and I've spent the last 4 years waiting for that hype to even come close to coming true. No such luck. The (few) other folks I know of who still ride Sora regularly also have had no problems with it even if it's not as crisp on the shifts as the pricey stuff. (My other bike is a DA, and it definitely shifts more crisply; I definitely prefer it.)