>>96344863
So what are the negatives?
Mainly that some certain parts of the AD&D system as written is obtuse and can lead to bad interpretations that run like shit on the actual tabletop. Namely initative.
That's where OSRIC (or if you're more autistic then going on Dragonsfoot and reading Gary's own clarifications) of things like how Initiative should be handled in the best way for actual play.

So in short my personal recommendation would be AD&D 1E and looking over OSRIC as well for simpler explanations of things like Initative.
Optional stuff like listening to the grogs at the Classic Adventure Game podcast describe how they'd run a game helps as well. They give some good recommendations about pacing and only running as much of AD&D 1E as you can reliably do fast-paced on the table, which is what most people here would tell you as well. (e.g. if you need to start looking things up extensively during the game to use Weapon vs Armor Class then don't use that system for now)
What's good about that is that you pretty much don't need anything else and you're set, even if you veer off into other D&D games later you have an idea of what the full thing should be like.
>>96344724
A lot of the AD&D 1E crowd runs OD&D as well. It's moreso the osrg discord that meme a bit about it. (if you run OD&D with everything and don't stick to 3LBB it pretty much turns into AD&D-lite)
Personally I just think that if you're coming from a newer system going to OD&D can veer you into running it like the newer game rather than something that fits OD&D but your mileage may vary obviously.