Depends where you are and on network congestion. With full signal strength on a good day, I seem to get 4-5mbps down (at least I did on my iPhone with the speedtest app, and whatever the WP equivalent was that's now gone), but normally I get 1.5-3mbps on an average day. You'll probably get faster speeds on T-Mobile.
Originally Posted by Terminatorbob
It's actually not unlimited everything, Straight Talk used to actually deactivate people's data if they thought they used too much, then if you called up and got your data reinstated and got caught using too much data again, eventually after a certain number of time's they'd just cancel your account, no refunds.
That's changed now, they appear to be throttling instead. I think if you use too much data and are throttled, you can call in, and they'll fix it but it'll only last for a day. The next day you'll be throttled again and I think this would last until the next billing cycle.
I use Straight Talk, but haven't run into these problems, but I have read about them from others who have. It's hard to recommend them because of the data thing, if you're a heavy data user, it's hard to recommend ST. Plus, if you really like T-Mobile's speeds, even though ST's speeds are decent, it's probably not close to T-Mobile (what are your speeds btw?).
What T-Mobile plan are you on if I may ask?
And you can read more about Straight Talk here if you want. Lots of information, but you kind of need to look for it.