It really depends what you want to do.
my main rig is a jcm800 2204 50 watt boosted up front.
As mentioned before the jcm 800 2203kk is a real work horse that thing comes with 4 kt88 tubes. It sound huge!
As far as my experience with 5150s I can only speak on behalf of the 6505+ it's a very dark amp but it sits a bit too low in the mix for me. However the mids are very pronounced. Its a very tight amp. Tighter than the jcm800.
what kind of artist from the 80s do you like to get a better idea. I'll try and record my jcm 800 and 6505+ so you can get an idea.