I haven't had problems even if my iPad 2 is slower than others. I did recently have to "hard reset" the whole thing about 4 months ago and that reinstalled the OS from and all the programs from scratch. After that it ran MUCH better, like brand new.
I've been camping on an iPhone 3GS for 4 years. it's been perfectly serviceable.... the main thing I see is that the 256MB ram limit seems to be the bigger problem with apps swapping in an out way too often now that the minimum supported iOS device is 512MB. There's no point bitching about "withheld features" because that's just how things work.