I noticed Patrick's reason for the choice of the Aggie was convenience, not sound/tone.

Then for recording where the sound/tone is under a magnifying glass, he chose the GB. Interesting.
We have PM'd on this and I thank him for his info and opinion. I had hoped that one of these two great amps would step out as a preferred favorite but that hasn't happened. It seems that only I can know what's right for me by using the amps, but there are none around. It looks like jbravo's suggestion to buy one from MF and return for the other if I'm not happy may be the way to go.
Love to hear anyone else chime in, and thanks to all who have posted on this subject.
Sorry. I guess what I wrote could be open to several interpretations.
If I had the spare cash and justifications for an Aguilar DB-751 (because I'm not in a band and I don't gig)... that's the head I'd use. Period. LOL.
The ToneHammer does sound better to me than the Genz. The TH is warmer, more classic sounding I guess...
The GB is ultra-clean and doesn't really color the tone.
Bass Central sent me the Genz - Grasshopper wanted me to try it and see what I thought. I like it. It's small, lightweight, etc... and has a bunch of features.
Do I prefer it OVER the Aguilar. No. Not at all.
Because I already own it and I figured it's better to have a spare laying around in the oddball case that I need one... plus I'm not big on re-selling things that are given to me. The Genz was a demo unit and BC told me to keep it since I do a lot of work for them... But still. I have income and I make money and pay my bills. So there's no need to sell something for the sake of selling it.
Anyway. Because I have it and it was just collecting dust. I decided why not connect it to the computer and use it as a pre-amp for recording.
Because I prefer the Aguilar, I love the warmer tone and the very simple setup and controls... it's a straight-forward, no need to constantly mess with the EQ settings, sort of amp... I use the Genz for the pre-amp and not the Aggie.
Sorry if I wasn't really clear. The Genz is a nice unit. Solid. Great features. Clean tone.
The Aguilar is a great unit. LOVE the tone. LOVE the simplicity. Not a lot of features but on a simple gig amp that you want to setup and play in under 2 minutes do you need them? The ToneHammer 500 has the sort of features the Genz does...
And the DB-751 is a Rolls Royce.
Between the Genz 210 cab and the two SL112 Aguilars... There's NO question which one of these two setups DOMINATES the other for tone. The Genz 210 is respectable and usable in a small gig situation.
The two SL112s CRUSH. They are like USA Spector Basses... even the hand-stitching is flawless. They're just a total different level above the Genz in my opinion.