Welcome! It's interesting what we all want out of bike, etc... and, of course, that's why there are a 1000 different bikes. I sold my Rocket (08 Touring model) in favor of the T-Bird. I gave up power, but gained in handling. From my experience (had a Rocket for almost 2 years and have had my T-Bird for 5 months), Triumph made a lot of improvements with the T-Bird. It almost seems like they learned from all of the Rocket's shortcomings, which aren't very many overall. I think you will find the T-Bird handles better. It's the best handling cruiser I've been on. Like most cruisers, however, it's limited in lean angle (scrapes pegs fairly easy).
As was stated, however, both are fine bikes and really just boils down to personal preference. IMO, Triumph is doing a bang up job with all of their bikes. I'd love to add 2 more to my stable (Street Triple and Thruxton), but I'd likely have to pay for a divorce if I brought another bike home. lol