We purchased the Rees Centron with wireless sensors about 8 months ago after researching several systems, including Temp Trak. We decided to go with Rees over the others for a number of reasons. First, the Rees software was, by far, the most user-friendly, fullest-featured, and easiest to use. Second, Rees has telephone notification for alarms (in addition to e-mailing, paging, and text messaging). Temp Trak didn't have telephone notification. This was important to us since the phone notification provides detailed information on the problem that's causing the alarm. Third, Temp Trak's (nor any of the other vendor's) Validation Package didn't compare to Rees'. Our QA was very impressed with how thorough the Rees validation was, both hardware and software. Since compliance was one of the main reasons for getting one of these systems, this was very important to us too. Fourth, we liked the fact that Rees had a local, direct sales rep in our area, 24/7 Technical Support, and a huge number of Field Technicians (I think they said somewhere around 60). Temp Trak didn't come close. Since we can't afford to be down for weeks in the event of a problem, this was a big factor for us. Overall, we felt like we'd have had to adapt to the Temp Trak system, but with Rees, it's adapted to our needs.