They are all so lovely, seen your pics!
Blue Rams are very sensitive and require mature soft water. I have never kept gold or Bolivian, but it is a well known fact that the Bolivian ram is a more hardy fish.
I have two Bolivian Rams in my 38 gallon tank. Quite honestly, they are probably two of the best fish I've ever owned. In my limited experience (had them about 4 months or so) I'd say they are very hardy and quite peaceful -- even though I'm pretty sure they are both males. They do spar (well, lunge/chase) one another, but there's no nipping and it doesn't last for long. I used to sometimes see them do little displays at one another as well (they probably still do this, but I haven't noticed) in which they'll lose their colour and their black eye and dorsal patches become very apparent.
They get along well with other fish and never attack them. If anything I'd say others pursue them rather than the other way around (though they're doing very well). Since I've bought them they've grown elongations from their caudal fins which are very attractive.
I've kept German Blues and they are far less hardy and actually VERY aggressive. Same goes for adult Kribs.