We upgraded from our second PUP in 2009 with a Roo 21ss. After some health setbacks we shopped TT's for a year before we decided to buy a second hybrid. We got the Roo 23IKSS. :)
Closing up in the rain is no big deal now, the canvas is permanently attached to the bunk end. Temperature control isnt a problem as long as you have access to electricity and use PUGS.
If you get a TT I'd suggest you look at the duobunks, not the skinny singles. My niece who has a tiny frame refuses to sleep in theirs, she prefers the couch.