A logo link might get more clickthrough if the logo / image is enticing or relevant, and if the link has sufficient alt and title tags you may get some SEO benefits too.
A text link is easier to control, obvious, and not blocked by image blockers / ad blockers. It's pretty much the standard link.
Here's a thought, as your a new-member and clearly a noob, try saying that from the get go. You'd get a far better reception from me, than posting what you did... Besides, "testimonials" from unknowns are BS.
MLM'ers (multi level marketing) would use these in attempts to make their products/services seem legit. Adding them to a site these days, generally lowers your credibility, especially in this gig.
Edit: My advice, don't go there...
Instead, invest your time in writing compelling, interesting and relevant content. That will get/gain you far more cred, than "testimonials" could ever hope to do.
Hmm I guess he talks about link from testimonial sites of affiliate programs like genesisaffiliates.com/partners-3/
I try to avoid those link farms as good as I can!
Try to appear as organic as possible. A mix of links and anchors is always good. Also, big G is getting good at reading images, so images/logos are also valuable.