The difference is that floor monitors, by design, mitigate feedback by angling the sound towards the singer but past the microphone (provided that the singer positions himself correctly)
Current exchange rates put you at about $750. For $300, I'd go with a pair of these:
http://www.zzounds.com/item--FEN0711270000 and another $300 on one of these:
http://www.zzounds.com/item--SAMXM410. Figure an extra $50 worth of cables, and call it a day.
With your budget, "warmth" and "sound quality" are not luxuries you can afford. This is a rig that will function for your current needs at your current budget, as long as you're not playing in a loud, raucous heavy metal band, in which case all bets are off.