With nearly 7k hours on Roll20 almost exclusively as a DM, I can say with absolute certainty that Foundry is by far the better product IF you're looking to get into the deep end of using VTTs. I'm talking special effects, animated maps, looping status effects, weather effects, all that fancy stuff... Definitely go for Foundry.
If you're just looking for something to hold your character sheets, help you with a dice roller, give you a dry-erase mat for basic and quick maps to help with ToTM, and maybe have some music and sound effect options, the basic (read: free) Roll20 account is more than enough to get you where you need to be, and probably a little further with a few extras you didn't think you'd want and that I haven't mentioned.
IIRC, the 5E sheets have D&D Beyond integration as well without the need for a better-than-basic account, but I'm... Not positive. Don't quote me. I don't run much 5E.
ETA: Combat support on the three big VTTs (Roll20, Foundry, and FG) is pretty much a core feature. How usable and how much you get out of it sort of depends on the VTT and what you put into it (I don't have any experience with FG, so speaking primarily about Foundry and R20 here), but they all do the basics like NPC stat tracking including health and AC. They also all have initiative trackers built in and other QoL stuff. Out of the box, neither Foundry nor R20 do any sort of easy encounter generation, but I'd eat my hat if Foundry didn't have some sort of 5E module to help with it and if R20 didn't have some sort of script (a paid feature). Both have compendium support though, which is going to be all your OGL content like rules and stat blocks in a searchable, encyclopedia type format. Roll20 lets you purchase rulebooks through them that add the non-OGL content in and Foundry I think you can just import it if someone provides it, but again... I don't run 5E so I don't know.