Price per HP doesn't seem to correlate to the value of the module for me. My first criteria is the performance. I'll often view multiple Youtube videos of the module in action to get a feel for the module: quality of sound, modulation, etc. The second would be features. If I have multiple ways to use a module that adds value to it.
I was shopping for a small quantizer due to limited HP space. I have 3 to spare. The toss-up was between a 2HP quantizer and the Erica Quants. The 2HP has more LEDs to indicate status. However, after diving in a little further, the Erica can generate a trigger each time it outputs a new pitch if there's nothing plugged into the clock input. The 2HP doesn't have that feature. With that, I can trigger an envelope based on the internal logic of the Erica... or some other event. That seals the deal for me. I get more value out of the Erica even if the price is a little more.
You'll spend thousands on modules. Each new module integrates with the others, so being frugal on one module might hamstring the value you get out the rest of the system.
I'm not knocking the price per HP system. But I'm thinking of the system as a whole rather than just a collection of individual modules. Cheers.