I have no thoughts or recommendations regarding the benefits of a high output alternator or the two alternators you found on Amazon.
As far as a recommendation for a seller, I recommend:
Ken Heming
M.A.R.S.
3701 E 69th Ave
Merrillville, IN 46410-3963
219-947-4038
hemi-roid@frontier.comhttp://myplace.frontier.com/~hemi-roid/He has rebuilt for $250 and new for $315 (high output). I'm sure Ken would be happy to discuss whether the accessories would require the high output alternator.
As for the alternators going bad, it seems to be a hit and miss. Ken Heming blames Hitachi relocating their manufacturing from Japan to China. Seems like the windings on some simply break for no apparent reason. Mine went bad on my 2001 Standard in 2009 after less than 15,000 miles. I've had no troubles since then with the rebuilt alternator I purchased from M.A.R.S.