if you think the H190 is better, I don't see how you will ever be happy with the H120. You will always think you are missing something. However you room is so small, I don't think this is the best way to spend your money, nor that the difference is significant. (Small in the amplifier need sense, not in any experience limiting sense) 75wpc Class A/B is twice of what you need easily.
I would save that money (the difference) for a speaker upgrade. That's your weak link and best bang for the buck.