Mine is specific to bands and had to be certain it matched my cell service. Mine also will do Wifi, but different band than cell. So I ask... Is what there are offering good for both?

No matter if it does one or both and matches the bands you require, if you have no signal where you camp, then there is nothing to boost. 

If you want a cellular signal booster look at the weBoost product line. I have a weBoost slim and the Wilson directional antenna which I mount on an extension pole to the flange of the trailer slide while camped. It works pretty well - as long as there is a signal to boost - but  not if you are down in a hole somewhere with no signal as olddawsrule says. If you want high bandwidth data service in the true boonies then the only real option is satellite, and mobile satellite data service is very expensive.