32 gb wifi or 16 gb 4g? That's a tough one. I usually recommend the 4 g because of the gps and the ability to get occasionally data when away from hot spots. I am grandfathered in the AT&T unlimited plan and my 4g comfortably gets 7+ Mbps and the lte has gotten 34 Mbps. However in your case, you are only looking at the 16 gb 4g. Between the operating system and apps, you can get mighty close to sucking up 16gb. If you add music and videos, you will definitely use it all up quick. I have found 32 gb to be a reasonable amount of storage. If you can swing the 32 gb 4g, you have the best of both worlds. If you really need to keep to $600, it depends on how much music and video you plan on loading on the ipad. If very little, go for the 4g. Otherwise, go for 32 gb wifi. If you do go for 4g, I would seriously look at verizon. They seem to have a much larger 4g and 3g footprint. Plus, you can still use it on a gsm network like AT&T or overseas.