the whole thing looks great, and obviously the competition is great for me as a customer.
the hand replayer looks incredibly sick, easily better than the competition that i've seen. you're right to prioritise this feature - on a day to day basis this is the tool i will use most. i assume you will include this, but on-the-fly pot odds are a must. if i can do a session review without using calc.exe, you will be a long way towards getting my $$$.
edit to say that useability in general will be the separating factor for a lot of people between HM and PEV.