I have the paid version - well worth it to get rid of the ads & support the developer in my opinion - and I don't get sponsored tweets. I am, however, looking forward to the upcoming release of Beta 8, which I understand is due later this month and I'm assuming is more than the minor fix release planned for tomorrow. We're pretty lucky to have so many good Twitter apps to choose from and Ubertwitter is among, if not, the best.
You still get "sponsored ads" in the paid version? That's what bugs me more than ads in the free version. I was planning on buying this when I update my phone but gee, I may have to rethink the whole thing. That's too bad...