I purchased a 3 bank 20A ProMariner (out of Arkansas) about 3 weeks ago. Wanted a Guest, but like others (only so many dollars) and the ProMariner was on sale (big discount) for the Boating/Camping sale.
I have been using it, and it works great. The ProMariner pumps 20A between the 3 batteries, load balanced to the condition of the battery. My first real tourney all day fishing event proved uneventful, and I had to really crank up the trolling motor later in the day with the wind.
All things being close or equal, I'd get a Guest. But with the $50.00 savings of regular price, and the difference in price from the Guest, it was an easy decision for me.
Tex