Frankly, the Delta3200 craps all over the TMax, hands down, ei1600 and upwards. For my usage (spotlights on people on stage, large range from bright faces to dark backgrounds and 90% of the frame is Zone 1), only Delta leaves anything noticeable in the shadows. With the TMax, I scan and I scan and pull tone curves all over the place to get something respectable, sometimes it woks and sometimes it doesn't, but the Delta just always works (that also means that if I ever do a real wet-print, the TMax will probably be useless).
Below ei1600 I haven't shot the Delta3200, only Tmax400 at ei800 and ei400. But I suppose that the same will still hold true even as low as 800, the Delta will just have more shadow detail.
As for lab pricing, it depends where you go of course. I shot some of my first rolls of Delta3200 at ei3200, gave them to the lab and didn't say anything, they devved at 3200 without asking and they were perfect. Next time I asked them to 'push to ei4000' and they charged me 50% more (even though technically the ei3200 rolls were also a push). Another time I shot at 6400, got a different guy at the lab dropping them off, he asked what ei, I said ei6400, and he charged me regular price. Haven't shot it since, but next time I'm devving my own so I won't have to worry.