I vote for the GM type one wire/self exciting style unit - umpteen zillion automotive enthusiasts can't be wrong. Jegs has one in black powdercoat for less than $100 with shipping and Don's Hot Rod Shop here in Tucson used to sell one for about $79. Despite the "brand loyalty" hoorah - all of these electrical components are supplied to the majors by vendors anyway - sometimes even from a common source! They are so cheap you can afford to carry a complete new spare.
Speedway Motors sells a neat little set of (plated and un-plated) brackets for a @#$% low mount set-up. I have now seen them used and adapted on everything from John Deere to Studebaker. I used one to make a RH lowmount for my T-bird and it tucks the alternator right down where the gen was. This is a "closed slot" with pivot style of bracket and very strong when mounted right.
To wire it in I used small #6 welding cable (right off the reel at the welding supply) with solder style ring lugs and high temp heat shrink for good measure. Run from the stud on the alterator direct to the battery connection on your starter solenoid. Be sure and put a ground strap from the alternator to the block - cheap insurance for max volts. I don't believe the self exciting style of regulator puts out the same high-end volts as the externally regulated version (by a volt or so) and this sort of "no-drop" wiring will just about make them equal.
Another good bit of advice I picked up - be sure the pulley on your alternator is about 1/3 the size of the engine pulley - you want it running about three times the speed of the crank. This is for a powerful street driven type electrical system - not a low geared race car. The self-exciter feature will not kick on until the alternator shaft reaches somewhere between 1500 - 1800 rpm - but once it is on, it will typically continue to operate even when the engine has dropped to low idle. The three to one ratio makes sure of this.
Steve Metzger Tucson, Arizona