Batteries have CDR (continuous discharge rating, measured in amps) and capacity (measured in mAhs). CDR is most important. What you need depends on the maximum wattage you're going to vape at. As a rule of thumb, divide the maximum wattage you will ever use the battery at by three to get the minimum CDR you need. Then find a battery from a reliable brand name (preferably recommended by Mooch) with the maximum capacity (mAhs) you can find for that CDR and buy it from a reliable vendor (preferably recommended by Mooch).
25 watts / 3 = 8.3 amps
So you want the highest mAh you can get in a battery with a CDR over 8.3 amps.
The best options for those criteria are these three:
- Samsung 30Q - 15A, 3000 mAh
- LG HG2 - 20A, 3000 mAh
- Sony/Murata - 15A, 3000 mAh
Those three will suit you very well, and you're unlikely to notice any significant difference in performance between them.
Just to clarify, the 'go for amps rather than mAh' advice mostly applies when you're vaping near the CDR of a cell. You only need 8.3 amps, so a 15 amp cell will perform well. If you were vaping at 40 - 45 watts and needed at least 14 or 15 amps, then you'd probably be better off with a 20 amp cell even if the capacity was a little lower.