I tend to prefer the really good American teachers for group classes. The really good American teachers tend to teach "concept" classes. I tend to get a lot more out of this type of class set up. The absolutely best of them teach concept and then a combination to show how the concept works in real time.
Korey Ireland is awesome.
I tend to avoid Argentine teachers now for group classes as almost every single Argentine teacher I have ever had, whether I thought them good or bad, teaches by pattern.
I like Argentine teachers for private lessons. The really good ones know how to get right to what's going wrong posturally and technically...even when you are wearing baggy clothes :-) And the couple we took lessons from (Gustavo and Maria) were quite good about beign hands on and fixed a few very importnat things on me and made me aware of something I'd been trying to do for quite some time. I'm still not perfect at it, but hey...at least I know what to go for now!
As usual, I found that even what people would consider "Intermediate" level dancers there are better than most of the dancers in my own town, especially concerning musicality, posture and embrace. (No one gave me a back ache there...as opposed to my first milonga back home, where I promptly ended up with a back ache after.)
Overall, I really liked the "style" of Tangofest. They had "milonga follies", a much more lighthearted approach to a milonga (early in the evening), where instead of cortina's they had skits of problems that are often encountered in the crowded milongas there and how to avoid them, plus encouraged people to dance with people they didn't know at all via cabaceo- sort of an Argentine version of a mixer. They also had a tango history movie made by the Argentine couple that we had gone there to study from for the week, which was informative and respectful of the past people who had strong influences in Tango without all the over-sentimental clap-trap and rose colored glasses. My only problem was my Spanish was so bad, I had to move up to the front on the floor to see the translations. All these extra-curricular activities gave the festival a more "complete" feel as opposed to just class, class, dance...class, class, dance.
One thing that was REALLY nice was the orchestra on the night of the Grande Ball. Totally changed my mind about dancing to live music. Well, if you knew what we had to put up with for live music here, you'd understand why!
It was a full orchestra composed of mainly dancers who were also serious musicians. The FOUR bandoneonists were Alex Krebs, Korey Ireland, Ben Bogart (ok- he's a master bandoneonist who dances a bit), and one other I can't remember. A local teacher played piano, and at least one of the string section was a tango teacher from California. It was LOVELY. They played DANCEABLE music with a good beat that didn't wander or drop in and out continually. No Piazolla, very little Pugliese and Pugliese-ish music. They understood that was not appropriate for the crowd level and played a lot of recognizable tunes...after all Korey did the arrangements.
Here's a link to the evaluation survey results from Clay.