Triton is good for upto 4S batteries and 2.5A max charge rate. Within those limits its a good little charger. (The Apache 2500 has the same charging capabilities for half the price, but doesn't do nicad/nimh cells or discharge/cycle).
The TP balancer can be used in 2 ways - 1 is to automatically balance a battery without a charger - you just plug it into the battery and leave it until the lights go out- couldn't be easier. The other way to use it is to use it while charging. As long as the battery you want to charge is not too far out of balance (again the lights will tell you) you just plug it into the battery during charging and charge normally. If the battery is both a long way out of balance and high capacity then you need to set the charging current lower during charge, but other than that its just the same as charging the battery normally.
I have the 5 cell version and use it on my 3S prolite packs. It works as advertised in conjunction with any lipo charger I've tried, including the Triton. I think it's a good precaution for extending the life of your batteries and its certainly more convenient than using the single cell charging method to balance. However there are plenty of people flying batteries that dont have any connection for a balancer and they still manage to fly and charge succesfully, so I cant tell you the balancer is a "must-have", but I would say it's a smart choice.