This is a
really simple question to answer, as it's subjective and doesn't really matter about anyone's opinion.
- Does your mobile provider allow tethering at no cost?
- If there's a charge, how much extra is it per month/year (vs additional cost of 3/4G iPad)
- Do you "need" (not just "would be nice") to have online access on the iPad while you're out & about?
- If you do, is it for long periods of time?
- If it is and you think it may afffect the life of your iPhone battery due to tethering, get a 3/4G model.
- If it's only for short periods (while grabbing a quick coffee somewhere), then get the Wi-Fi model and tether to your phone.