Well, for an opinion the other way, after seeing what the Krokodile Cart does and from the description of the Harmony Cart, I would have bought one even if it was $200. I did buy one at the current ~$50 price. I'm not into the 7800, but if I were, I think any price $200 or less would be more than reasonable.
Even with the deluxe package, the Harmony rolls in at about $50 cheaper than all the other flash carts for systems. That made it attractively priced, especially since I want to play the games I made on a real machine. At $100 (or $120 for the deluxe) I probably would have still bought it, but I would have thought about it more. As it is though, I am thoroughly happy with my product and the people who have seen it so far have really been impressed. One enough so that he may buy a 2600 just to be able to use the cart and some old joysticks.
What's important is not how much "I" would have paid for one, because that only constitutes one sale. I'm sure we could find someone who'd pay $700 for ONE. "How much will a lot
of people pay for one" being the relevant question. I hope a lot of people buy them, and I think at $50 they are going to continue to sell for some time. I think that's a great price. As someone commented earlier, hats off to the developer. I'm not into the 7800 either (yet) but the way my interests are going (retro) I keep saying I want a new system (360, PS3, etc) but I keep buying old ones. If one were available for the 7800, it would certainly pique my interest in the system, like the 1541 Ultimate did for the Commodore 64 and SIO2PC got me back into 8-bit Atari.