I have the Hawkins Precision Hybrid Rings on a Tikka. They are like Talleys on steroids with an integral level. On a hunting rifle, I like that the level is not sticking off to the side.
No experience with them, but I've been looking for something for my new Mark 5. Hawkins has the combo rings mentioned above as well as picatinny rings both with the integral level.
I just picked up the integrated level for my 30mm Talley lightweights. Seems to be ideal in that it's not too high to totally obscure the turret, though I could see that being an issue with a different scope. Haven't had it out of the house yet though, so hard to give a full report.
it's tough to beat the Hawkins. I personally think the level is fluff on my rifles as I NEVER look at it and if Andy sold them sans the bubble.....I'd buy it.
Anything with the bubble on top is not ideal IMO. The ones i've seen are not easy to check without coming off your cheek weld or they obscure your elevation dial. Because of that I'll take a separate level every time.
If there are any with an offset level that can be used without lifting your head off your cheek weld I'd be interested.