How would a HD 4000 handle working at 2880x1800 or 3360x2100? Would it be wise waiting for Haswell?
How does the 15" rMBP handle the 1680x1050 resolution using the HD 4000? I guess the 13" rMBP would have the same behavior.
Performance is fine at least for Web Browsing and Microsoft Office, and scrolling is very smooth. Problem is, the 15" rMBP automatically switches over to the 650 when I try to do anything intensive. I know I can forcibly turn off the 650 but this is an Apple store machine, and they won't let me install anything extra.
If you can wait, then wait. The next generation will always be superior. I'm not going to wait because when Haswell comes out, something better will already have been planned. I don't intend to wait my whole life.