The high def picture it produces is actually quite acceptable. The rest of the features/functions are frustrating but depending on how much you paid for it, you might find it acceptable as well. I paid $135 with full shipping and handling so it was worth the try.
1) yes blind scan is slow and not very good. In fact, I don't blind scan with it. I usually depend on someone else to find the feeds for me and then just plug in the numbers. Other option is to blindscan with say an old Fortec and then use the numbers it gives in the Neusat.
2) I can confirm that you can convert a Neusat to a Captain 8000HD. The interface is almost identical, just a little uglier. Same little glitches and qwerks, as the Neusat interface. Only risk you are taking, is if the Captain decides to install any kill codes. The Captain firmware, however, appears to be fine for now.
3) The biggest problem with the machine is the inability to add a satellite to the satellite list. For example, Horizon 2 is not in the current satellite list. The only way to get H2 is to Drive to 74W using your remote. This is pretty tricky to do, and you lose your settings once you go back to a factory setting, so it is not very practicle.
4) If another alternative was available, at the price, I would obviously switch. I'm inherently cheap, however, and I'm not ready to shell out $300 - $400 for a HD receiver.