Like many have said go with a GPSr with more features then the ipad as far as geocaching appliability. Yeah now a days you can get 3g and 4g non-wifi ipads, but try looking into the Garmin Oregon seris. An ipad just wasn't made for geocaching, it was made first to play games on then moved to a compact laptop now they have Geocaching apps out. Overall if you have a use for an ipad and aren't to into geocaching go that route but if you plan to do a lot of future geocaching go the upfront pricy way.
If you end up buying a GPS I would say first pay the REI $20 for a lifetime membership, then buy it at REI eaither in store or online. My reasoning behind this is yes GPS companies have ok warentys but REI if your part of their membership co-op they stand behind the products they sell. For example I have gotten many things replaced including GPSrs, tents, boats, eta that wouldn't work anymore just do to constant wear or that just finaly fell apart.
(No I'm not sponserd by them, I just want you to get the best deal for your money)