Don Best Premium is the Ferrari of lines services. It is amazing to me the vast amount of information that it makes available right at your fingers.
I like using it for bases. I look at the lineups for the day, take the 1st base ump, who will be tomorrows home plate ump and then look at his Over/Under stats. I know Covers has umps also, but it isn't easy finding the Umpires for the next days game. I'm sure there are other ways, but Don Best makes it easy. That is also about 0.01% of what you can use it for.
Don Best Premium is a lot more than just updated lines, which is what I see on the other lines services I have looked at. They have stats up the wazoo.
I also think that DB Premium is the best service for finding out injuries. They do an excellent job researching. It's impossible to know them all, but they do a good job of finding out what they can. If you personally know the trainer for a professional sports team, you might get better info, but that's about it.
By the way, I use Premium and have a Pinnacle account. Don Best gives the line up to the second as far as I have seen. I will say that Pinnacle has lower juice than most and will tend to move the vig numbers, so Don Best doesn't always show the juice numbers. In other words, Pinnacle might have an NBA team -4 -107 and Don Best lists it as -4. They may have another team as -4 -103 and they list that as -4 also. That's the only "problem" I've ever seen and I don't think that is even a problem.
I can't see a sportsbook operator not having DB Premium, although as a player, I wish they didn't.
David