It recently occured to me (considering OD&D, sans supplements*) that B/X just might be the thing to play if you want the OD&D experience without having to decipher Chainmail (not necessarily enviable) or shoehorn in your own houserules (a more palatable option for many given the hobby's demographic). How so? Here's why I think it's best:
(1) ABILITY SCORES are simple and streamlined. It's modifiers are satisfyingly complete while avoiding AD&D's bloated approach. Exceptional strength might be cool (nothing compares to rolling that 00), but is it really a necessary thing? My mind goes back to Spinal Tap, where Nigel's amplifiers hilariously went to 11. In B/X you know almost immediately how well your character can read and/or speak. Wisdom is genuinely useful to non-clerics, and everything fits on a convinient page in purest OD&D fashion.
(2) CHARACTER RACES make better sense. Race as class was a technicality. In OD&D dwarves and halflings could only be fighting men; elves could progress as fighters and magic-users subject to some incomplete rules, but it wasn't spelled out (and difficult without the Chainmail reference). B/X gives them all armor and weapons, making each de facto fighters with racial abilities added. Race as class? No. Class restrictions simplified? Yes.
(3) ALIGNMENT matters. And gets explained. I know it was originally concieved as faction, an approach so denuded of meaning as to feel unsatisfying. This might be a (relatively) modern innovation; but given its close proximity to the original texts, it certainly has to reflect approaches already happening at the table. I tread cautiously because I wasn't there and welcome wiser minds on the subject; but it certainly feels like a refinement of OD&D's style, which it is by definition even when different from Gary's original rules.
(5) LEVELS are capped at 14th for humankind, with all others mapping to OD&D's admittedly more limited offerings, although dwarves and halflings get a better deal. Men & Magic took players to 10th (16th for magic users), so everything translates. Both iterations invite the DM to extrapolate beyond that; and while accidental in B/X, which promised a later companion fulfilled by BECMI, it nonetheless clones OD&D's ceiling in a real way.
BONUS IMPRESSIONS (or why not just use BECMI instead)...
(6) ARTWORK by Otus and Willingham both preserve D&D's early and more amateur aesthetic while improving on its filched comic book style. I have nothing against BECMI (it's the same mechanics from the same publisher); but Elmore's steadfast professionalism marked a clear shift towards something else. It's a sound choice (and he's a talented artist); but I do miss the greater variety of the earlier stuff, although it's purely subjective.
(7) BECMI led the game beyond ordinary people under extraordinary circumstances, and while this might have been brewing early on (I'll defer to the experts), it doesn't feel like anything OD&D - or any of its supplements - endorsed. Again, there could be a mountain of proofs against this charge, but BECMI clearly shifted gears (speakers to 11). Now it's not remotely lost on me that B/X planned to do this; but accidental or not, B/X is what you play when you want a cleaned up and clarified OD&D that feels truly vintage...
All of this is academic, of course, as B/X and BECMI were seperated by mere years, and both from OD&D by little more than a decade (attesting to its rapid growth). But it really speaks to the combination of objective and subjective criteria that make a game feel right, and even then it's all someone's opinion. But if contemplating OD&D, B/X delivers.
*If you want OD&D and its four supplements, AD&D is the far better choice...