Precision
Basically speaks for itself BUT
Balance
This is the velocity regulator (distance regulator enabling deeper scale length putts to be as close to shallow scale length with shallow being the most reliable). A nice slow (shallow meter) strike will be pretty consistent on several putters. Start revving this (deeper meter scale) you need more balance (more consistent shaft if you like perhaps). EDIT: Broad generalization and always best to try before you buy.
Forgiveness
Should speak for itself but it's fickle between putters. My current putter I think offers great forgiveness for short range tap in putts with a shallow meter. Best to be more careful with a deeper meter, especially across face.
Meter increments (scale length offering)
Whatever floats your boat - last thing I look at as soon get used to any.
All that said it's then a case of learn your putter after choosing what is likely in your ball park of suitability. And all that said I think the L70 Versa is a super little putter that is possibly the last meaningful word, and everything after might be fluff......Speaking of fluff I hated the L96 Versa but very much like my Sabretooth so go figure. A fine enough putter in my place loves the L96 Versa and hates my Sabretooth..........Very personal basically.