I have MetroPCS 3G for cellphone service and yes its nice to have Mobile Web for emergencies with WAP access I still use my laptop or IPod Touch on WiFi.

I find the 4G speeds to be quick but not as quick as WiFi. When the internet at our house went out I went to a Starbucks located 3 minutes away and used their WiFi. I have a list of WiFi Hotspots that are reliable.

The local library gives unlimited WiFi but limited computer wired access using their computers and I go there as well.

My point in case is if you have WiFi you will get much better and more consistent speeds using WiFi. Especially for streaming audio or video your best bet is having a laptop or netbook.

I use my Cellphone in the car for web to check on traffic, weather and get maps while driving.

4G can be slower if the signal strength is weak just like WiFi. At least with my ATT DSL I can access all ATT hotspots for free but since Starbucks is free anyways no problem.