[vldx]

I'm currently with rMBP 13 and I'm using it mainly for web development, as UI/UX stuff also.

The screen size is not an issue for designing; you can switch to more space, e.g. when designing I'm switching to 1680x900 and don't feel claustrophobic as on my previous MPB's 13".

I had high-resolution & anti-glare MBP 15", just before buying the retina, so I'm comparing it with the 13" rMBP and actually the retina feels more comfortable for designing stuff. Weird, heh?

I would max out the ram and SSD and go for the 13" model.

[askar]

Thanks for the great advice. Eventually that's what I did, maxed out the RAM to 16GB and upgraded the SSD to 256GB and compromised on the 13" screen size. Apple Live Chat person said try this and see how you feel and if not then upgrade to 15" and I thought that kind of make sense. I hope I find 13" comfortable; otherwise I have to shell out another $500 for the 15" similar spec.