Re: Help in picking out a 7 or 8 string guitar
Another +1 for the 7620 if you like trems and the 7621 or 7421 if you don't. The 7420 is a fine guitar and can be found cheaper than the 7620, but not that much cheaper and the 7620's Lo Pro is worth the extra cash. You can upgrade the 7420's Lo TRS to an OFR, but by that point you could have just bought a 7620. You should be able to find a 7620 for ~$400-600 depending on the condition, color, etc. That's a really good deal for how nice those guitars are.
But I wouldn't say that they are the nicest 7-string below the $1,500 mark. You'll have to search, but you can find the original, square heel Universe guitars for around that mark (or less for a beater). Despite being made of the same woods and having the same trem as the 7620, IME and IMHO the older UV7 sounds significantly "better." I've owned/played several examples of each, and the UV7s are consistently bigger and warmer sounding IMHO, and by a large margin.