To stereo or not to stereo, that is the question. If you play keyboards or even guitar that uses stereo type effects you are missing a lot if you use a dedicated keyboard amp. If you are just fooling around or gigging small venues then a keyboard amp with a 15" is good ,I like the Roland too, but sold mine to upgrade.The new Fender passport system is hard to beat for just a solo gig or playing at home and is a good alternative to the Roland amps because you go out in stereo. If your doing any kind of recording at all then I would NEVER use a mono amp. The events are pretty decent speakers by most accounts for home recording. It really very subjective when it comes to what a good monitor is. If you want one of the best and have the $ go for Mackie.
I have a couple of Communitys on sticks coupled to a 1000watt amp and thats all the loud you will ever want at home.