Honestly in the event that OSRS gold you've never tried either, try them aside from the world and the lore and the set of abilities to train they've basically evolved into two entirely different games, osrs in my view is just way far less generic and ridiculously over the top, plus it's exactly what most older players actually know, and what they fell in love with to begin with.
I would vouch for one to attempt OSRS, in case you do not mind the mill, it's over 2x the playerbase and isn't infested with MTX, unlike RS3
Don't get me wrong, there's far more to being a fantastic RS player than having a sizable cashpile, and a lot of what really counts can't be bought with gp, but using a sizable cashpile since you spent like $100 on MTX will surely give you an edge over players who don't buy MTX, regardless of which version of this game we're talking about.
If you want to grind endlessly osrs if you are looking for Rsgoldfast a more contemporary casual encounter rs3vFor an MMO that I can just kind of drama to enjoy, I've always favored RS3. It cut back on the grind and pushed more of the high level stuff/combining things for greater efficiency and less work. That's part of the reason why some people today hate itThey really take pleasure in the grind. To get grindy stuff, I have always preferred Monster Hunter, where it has less amount of grind and much more problem of mill.
There is not any definitive answer to this - the very best way will be likely to play both for like a month per day and watch for yourself, then pick 1 variant to continue if curious.