Thanks for that, I'd already done it--the Star Alliance lounge was TAM but now because TAM is joining LAN and OneWorld, I think that is changing to the GOL Smiles Lounge, which is just across the hallway from the TAM lounge, at least in the terminal where Turkish flies from.
The Lounge was actually not bad, with a few interesting drinks (frozen Caiprinhas and Caipiroskas with fresh fruit!) and pretty standard packaged snacks and sandwiches, nothing special. I saw no English newspapers or magazines. Flight was announced for boarding, though by the time I got down to the gate they still weren't boarding for another 10-15 minutes.
Check-in was odd, and annoying--but I do know the guy was just following the rules: He asked me if I was checking any bags (the exact same bags I carried on UA in Y- with no status 4 days earlier) and I said no. Then he asked me to weigh my carryon bags. He said the weight limit is 8kg. The last 3 times I flew Jetstar and Air Asia, which actually do sometimes enforce this rule, they didn't even bother to weigh the bags. But TK at GRU did.... for a flight that wasn't full. (?) So I had to completely re-pack my carry-on and other bag, since I was bringing a coffeemaker to a friend. I did it, and that was fine, just a bit of a headache.
The best part? He said, "It's not a problem, the coffeemaker won't break, I'll put a "FRAGILE" tag on it. Now, please sign this baggage tag that says it's not TK's responsibility if your Fragile bag is damaged."
Huh? That did make me LOL.
Suffice it to say I carried the important stuff through, and the bags arrived reasonably quickly at EZE.
Inflight service was OK in Y, not great, and the food, while edible, wasn't on par with the nice Do&Co food I'd gotten used to on ORD-IST-ORD.
IFE was super messed up--every movie in the listing seemed to be there, but when you pushed play, a different movie came up! Still, I found a good one and enjoyed it.
I'd say for the price ($249OW, much less than QR ($305) and especially less than JJ or AR (like $400-600!), TK did the job.