We're contemplating downgrading our service tier from Enterprise to Premium - are there any notable drawbacks in doing so? (We are using way below the Enterprise monthly transaction lines, full licensed users, etc.)

No, but I'm sure your account rep is going to come up with all sort of bogus reasons why you have to be enterprise level, as they'll be missing out on tens of thousands of dollars in essentially free money. Only other less publicized thing I'm aware of is that if you're on Standard you can't change your release dates, but that shouldn't matter in this case.

That was my thinking as well @James Morris out of curiosity, any idea what the average cost per license is for premier vs enterprise?

I believe it's just a flat charge they add on to your bill not a per user thing. You should be able to see it on your most recent estimate or billing statement. IIRC from my last job it was about ~20k/year additional when we went from standard to premium, but that was like 4 or 5 years ago, so take that with a grain of salt.

Thanks for the insight on the release dates by the way, I wasn't aware of that

I'm showing premium tier as ~60k/yr list price (before discount).

The number of Suite Cloud Plus Licenses are also tier dependent

Would be interested to know if you're successful. We've been arguing with them for years about this. As well as the usage metrics they also try to argue it's based on 'company' size and trying to include other companies in the group. Those companies are all on different ERP systems and have no connection to our NetSuite footprint.