Rat,
I started with a TT 15 years ago and have been pulling a 5er for the last 8 years. Yes TT hitches have improved over the years, the Hensley Arrow is supposed to make a TT feel like pulling a 5er. Personally I like a 5er, it just fits our style of RV'ing. But they are big trailers on average, tall, most at least 10-12' height, and heavy, the new ones seem to keep getting longer and heavier every year. TT on the other hand are lighter in weight generally, smaller, shorter in height, and don't take away the bed of the truck as a 5er does. Pulling will be different because as you know from your 5er, it seems to be part of the truck and does not sway in the wind. On the other hand, a TT will to some extent have wind sway, tail wagging the dog feeling. Other than that, there will be a slight difference in backing as the TT will turn quicker than the 5er. Your hitch weight will vary with added weight you put in the TH causing the back of the truck to squat a little more than a 5er will because of its attachment point. Think about an airbag setup for your truck, it just helps with leveling. But with a good quality hitch and sway control, you should be fine. You definately have enough truck. Just remember, don't always go by the weight sticker on the trailer, as most are going to be off because of added items. And with TH'ers, it's what is added by the owners, TOYS and STUFF, that really cause overloading. What ever your decision, enjoy!!!
Clark