I have several TT collars. a 100 lite, a Flyway, a Pro 500 and many dummies and bark collars. I have a Dogtra Model 500 and I have Sportdog Prohunter 2400.
I have owned several other TT collars and an Innotek 500r (for about 2 weeks).
I do not like the feel of the Dogtra Transmitter, it's just a pesonal preference. I have used the Sportdog more in the last 2 months than the others combined.
Cray