I would suggest taking an actual measurement of drawlength on your Hornet, if you haven' t. Diamonds are notorious for being longer than stated (usually a full inch). The draw cycle on the Merlin is very nice. It definitely feels like you' re pulling less than an equal draw-weight Diamond. How much less, I really couldn' t say.
As far as noise, I' ve always thought Diamonds were on the very low end - until I heard a Merlin with the new omega cam. It' s my friends bow and he has this Hunter' s Quest 35 set up for being quiet. He got the full aray of Sims products on it, no rubber peep cord, and nothing on the strinp except a stringloop. He has a 7" Doinker on it. In this configuration, it' s the quietest bow I' ve ever heard, and I' ve heard them all.

I should mention he put a custom string on it, and that made a noticable difference in noise level.
By no means is it a speed bow, but it' s no slouch either. The 31" Hunters Quest is faster if you want the speed and it' s very similar in length to your Hornet.