I gotta go again, but I think.
Haswell rMBP is not for me. I wait to return it, I will till next week to do so.
Gaming wise it slightly better.
For OpenCL it is majorly better.
Everyday use should be on par.
So if your looking for a new laptop and don't have the Ivy Bridge rMBP I would.
1.) If your not into games at all, or apps that heavily use OpenGL, get the base Haswell (with a memory upgrade)
2.) If your into gaming and need tons of OpenGL performance, based on your budget I would get either a refurbished Ivy Bridge or if you can afford it, Haswell 2.3 rMBP. Choosing between Ivy bridge and Haswell is about performance/price, I think Ivy Bridge beats Haswell there, but if money is no object go for the Haswell.
If you already own a rMBP, you don't need to have envy. It seems Apple Laptops have 3 year cycles before you truly need to upgrade.
The only case I would get rMBP if you truly depend on OpenCL.
Alright guys, feel free to post your own reviews. I look forward to reading others. I might update this thread next week, if my opinions change.
Notes: Please upgrade to Mavericks if you have a Ivy Bridge rMBP, it fixes most of the lag issues.