I find the Tab's display more than adequate. The colors are vibrant (saturation can be adjusted) and the white/black levels can be configured too.
The IPS technology used in the latest Apple products offer better viewing angles (in terms of maintaining color and contrast), whereas the Tab's display tends to wash-out some details. That being said, it is still amongst the better displays, nothing deal-breaking. There's also a slight issue with regards to refresh rates, which creates a tiny bit of ghosting, particularly visible with text rendering. Once again, it's a really minor issue, just being picky here.
Overall, I absolutely love reading and playing on the device, the screen is simply beautiful. I haven't tried outdoors yet, but I guess it's like every single multitouch-display out there: it sucks !