I use 3 of these actually: DraftKings, BetMGM and FanDuel. I also use William Hill, but will ignore that here, since you didn't ask about it.
DraftKings came to market first in my state, about 2 years ago, so I've been using that the longest. Also, full disclosure, I own stock in both DraftKings and MGM.
So in all honesty, I like all 4 of the ones I use. They all have their pluses and minuses. But they have all vastly improved from when they first came to market. DraftKings has the best promos, I'd say. For instance, the first 3 weeks of this NFL season, they have given you a 20% profit boost on every single NFL game. I'm not sure how long that will go on, but it's been cool. They do a lot of profit boosts. FanDuel has some too, but I don't find them to be as often.
If you are into alternate lines on games, DraftKings and MGM give you a lot of choices, both point spreads and totals. FanDuel doesn't offer as many (ie: an NFL game, will give 2.5, 3.5, 4.5, etc. Not like 2, 3, 4).
DraftKings, in my opinion, has the best variety of player props, if you are into that. FanDuel probably 2nd most, and MGM the least.
I've deposited and withdrawn funds into all of them very simply through a bank account. I haven't withdrawn funds from FanDuel (used that one the shortest time), but for DraftKings and MGM I got the money within a day or 2 max, back into my bank account. Not sure in Tennessee if there is a brick and mortar sportsbook location, but here, you can deposit money in person too. I believe withdraw as well. But through the app is so easy, I don't bother.
I didn't answer too much probably, but my recommendation would be this. If you can download any of the apps in your state just to browse, do so ahead of time. Look at the layout and what is offered. I personally use 4 different ones, because I like to shop for lines. It's not quite my older days of walking the Strip to find the best line, but I enjoy finding the best line I can on a game. So I place bets in all 4 of my books that way. For these MLB playoffs for instance, I've experienced a significant discrepancy from book to book. So I like to shop around.
For me in level of usage, I would say DraftKings #1, MGM #2, William Hill #3 (not in your state I guess, but for comparison sake) and FanDuel #4.
Anyhow, best of luck in what you choose. The three I talked about here are all highly reputable in my opinion and I like them all.