As we all consider battery life a key feature, it might be worth taking a look on how well the new iPads perform while using the LTE Hotspot feature. The guys at Anandtech performed such a benchmark using a 100KB/s constant download from a laptop tethered over WiFi to the new iPad mini with Retina Display and respectively the iPad Air.
During the test, the iPad mini’s display was off and no background syncing was taking place for a more accurate result. Both access points are more or less identical to between both iPads, with the Retina mini using a PoP implementation of Apple’s A7 and Qualcomm’s MDM9615M modem, having the big difference noticeable in battery capacity. The iPad mini has a 23.8Wh battery compared to the iPad Air’s 32.5Wh. The results are as following:
Taking a look at the iPad mini first, it lasted roughly 18.77 hours on a single charge, compared to the 24.08 hours scored by the iPad Air. But the gap between the two is mainly due to battery capacity, therefore the best option would be the iPad Air. However, if you prefer more portability, then the iPad mini would be the more suitable candidate.