i can vouch for the roland cube80x and marshall 8020.
the roland cube 80x is very versatile. the clean channel, it has lots of headroom (check out the youtube videos that compares the 80x to the ZT Club) and has extended bandwidth. almost hi-fi bandwidth actually, so it also amplifies acoustics and organs well. i hav't tried it for bass guitar but it can probably do well too. the clean channel also takes pedals very well. the modelled lead channels sound good as well; but IMHO only sounds good when used stand-alone... the lead channels sound compressed if used with gain pedals. the biggest bonus for me is that i sometimes use the amp as a make-shift PA system... that is, have an external device playing tunes through the AUX-IN, then you can plan or sing-along using the regular isntrument-in.
the 8020 on the other hand, is just as what the others have said. ok on the clean channel, and great on the overdrive channel. but you need to mic it in order to keep up with a drummer live. also, it has typical mashall bandwidth (limited bandwidth, and middy sound), so its only great for guitars or perhaps harmonica. so naiba ang strengths niya sa roland... in fact i consider it as the anti-thesis of the roland.
overall, i tend to appreciate the roland more because of its verstility. IMHO, if you want a dedicated guitar amp whose strengths are better suited for guitar only, then its better to get a tube amp... especially that good low-priced chinese-made tube amps are now available.
so just to share, here are the qualities that a look for nowadays in a good versatile solid-state amp:
- big clean headroom
- wide bandwidth (capable of sounding good with a range of instruments)
- connectivity options for aux-in and recording/headphone-out.
- relatively lightweight (compared to tube combos)
- the quality of modelling and effects are not deal-breakers for me. i'd rather that it be good on the above characteristics to promote versatility.
