I've been calling for a long time, and the only time I use an electronic caller is when calling bobcat, due to bobcats usually like a more continuous sound and you can't get away with any movement, cause cats tends to hang up and watch before they commit to the call. Therefore it usually takes cats a little longer to come in to the call, and using a mouth call will wear you out.
On yotes, I have had very good luck with a verminator tweety, I don't know why I've called in more yotes with an open reed mouth call, it's probably the lack of emotion in the electronic caller. But who knows. That's just my experiences.
As for which electronic caller, the FoxPro is the best. I've had the best luck with the blue bird sound for cats.