You do realize there is room between suck and not as competent as the clone troopers right? It's not a dichotomy.
Well it's also easy to lump all stormtroopers together, when in reality, they have a lot of origin sources.
It's important to remember that at the end of the Clone Wars you had 2 separate sources of clones: Kamino-born (10-year training program including flash learning along with field training); Coruscant-born (secret Spaarti cylinders on a moon of Coruscant, clones grown to fruition within a couple months and all training was via memory flash). The latter being created so that Palpatine didn't have to completely depend on Kamino for new clones, and also explicitly to breed a huge army to be the backbone of the future Empire's military, as opposed to being bred to win the present war of secession.
The latter are far less competent than the former.
Following the Clone Wars and the Kaminoan rebellion, Palpatine decided to diversify the clone stock from just Jango Fett DNA. Multiple new clone templates were created from his favorite underlings, grown in Spaarti cylinders and given flash training. In addition, the Stormtrooper Corps took recruits and probably conscripts from many worlds, so that the original Kamino-born Fett clones who made up the core of the Corps at the end of the Clone Wars were a small minority in 0 BBY. In fact the only pure, original set of Fett clones was the 501st Legion, Darth Vader's personal command, and included clone troopers who didn't retire plus the original clone commandoes and Alpha-class ARC Troopers.
The "old guard" of Kamino-bred troops had extreme contempt for the stupider Fett-clones flash-bred in Spaarti cylinders, the additional gene-line clones, and especially volunteers/conscripts. I would expect facing a 501st detachment, as on Hoth, to be far more dangerous than a bunch of volunteers with basic training but not hardened by the Clone Wars.