"He claims the new Nimble SAN can take VSS snapshots every 1/2 hour and be much easier to recover, even to point-in-time. ".
If he is willing to give you a written confirmation then that these will always be 100% crash consistent then ok but as I say I've seen these go wrong, all it takes it the following time line;
00:00 - VSS snapshot 1
00:05 - Transaction 1 opens but is not closed yet, its a big update lets say
00:06 - VSS snapshot 2 comes along and freezes the IO. Our 1 transaction is stuck open
00:07 0 Transaction 1 closes after the IO resumes.
Can you guys 100% state they can get you back to 00:06? and if so what will happen to the transaction?.
As I say its our job as DBA's to get the data back if needed. If they are insisting you use something your not sure about then insist that they put in writing its not your fault if the backup file is no good and cant be used.
Just my opinion but stick native, that keeps you in control of knowing your backups are good.