I transferred out of a T4, but didn't have a horrible experience. The downsides to T4s are pretty uniform.
1. Often have severely limited initial job prospects
2. Career Centers are unable to extend much help to those not in the top 1/4 or so of their class
3. Your classmates are not all dummies who you will easily dominate
4. Scholarships can be hard to keep
5. Grades are often extremely deflated, you can go on AP or flunk out rather easily
The combination of these factors keeps things competitive and tense in ways that students at higher ranked schools will never understand.
What was good for me?
1. Classmates were great
2. School was in a sleepy/friendly town
3. Instruction was very personal, you were a name/not a number
4. Education was more 'nuts and bolts' and not steeped in theory (more emphasis on local bar)