I travel oversees quite often, so I've never got to think about LTE option.
But really, I'm not sure how many users are satisfied with current 3G or 4G iPad models, since most likely it costs about $15~50 every month. I'm not saying all of the places are equipped w/ their own wifi. But my office does have one, and most likely I wouldn't use it while I'm driving.
I have my iPhone, which is costing me about $80 per month, and I think that's really unreasonable price for communication-only. I don't use SMS, I have iMessage. I don't use phone call, I have skype. What about data plans? I'm paying for 2GB for $25 or so. I don't think it's reasonable price to pay, but if it is mandatory to get my hand on iPhone, so be it. (If you have contract, you pay less for the actual phone as well)
But iPad isn't like iPhone. You can get iPad for reasonable price, you do not have to pay extra for not being on contract. Paying extra money for LTE antenna and monthly data bills don't seem to convince me that much.