I can't try 3840 x 800 since I have the analog TH2Go... :(
Yes, three 4:3 monitors is better. I'm still pretty happy with my setup anyway but I wish I had known more than what the Matrox site told me in its FAQ...
http://www.matrox.com/graphics/en/gxm/products/th2go/faq.php#10
Do I need a special brand of monitor?
TripleHead2Go can be hooked up to any monitor, including flat panel monitors. To take full advantage of TripleHead2Go, we recommend you use three identical monitors (that is, monitors that support the same monitor settings such as monitor resolution and refresh rate).
Maybe I should ebay my analog one and get the digital one?