hello there, i will share my experience with both an iPad 2 wifi-only and an iPad 3 LTE
i owned an iPad 2 wifi for about 6 months - bought a refurb back in May. i have an iPhone 4S that's jailbroken so i have free unlimited 3G wifi tethering. whenever i needed internet on my iPad, i just switched on the wifi tethering on the 4S settings and boom, i was online on the iPad. problem is, whenever i had to use my iPhone to make a call the connection would drop out. sometimes it would automatically reconnect, other times i would have to manually turn the tethering off, then on again. after about 6 months, it started to get on my nerves. free is free, but it started to make me less productive combined with the fact that wifi tethering destroys the 4S battery.
i gave my iPad 2 wifi to my brother and i bought an iPad 3 LTE model last week. i am doing the 1GB for $20 prepaid plan. once i reach 1GB i will just switch back to wifi tethering to my iphone until the next billing cycle comes. for $20/mo to be able to have my iPad have its own independent internet connection is definitely worth it to me, plus the fact that all content on the iPad 3 LTE is always up to date to the second. for $20/mo - it's worth it to me. now i did pay an extra $130 to get the LTE model, but keep in mind, you will get a chunk of this back in resale when you sell it
my suggestion is this - if you have the extra $130 to spend on the LTE model...DO IT. you can always decide later if you don't want to subscribe to a LTE prepaid data plan. but having the option there is key. what if you know you won't be near an outlet all day but you need an internet connection. on your iPad you can activate the verizon (or AT&T) plan instantly, boom, now you have 1GB for $20 or 2GB for $30. once you are done with it, you can either ride out the rest of the month or call up verizon to cancel. they will give you a pro-rate refund back for the unused portion of the data