Rs3 on the other hand has mtx, slower updates, stagnant RuneScape gold participant count, which is harder to get into with all the interfaces and layouts you have to work out, but after that is passed RuneScape game has much faster xp rates compared to osrs, but nevertheless requires hours to achieve certain levels, the combat is comparable to other mmos, being keybinds and abilities and so on, bosses are diverse and engaging for mid-high level RuneScape gamers, pvp is mostly dead nonetheless, also has more abilities and quests to research.

Both games have a style called Ironman, this gives you the limit of not having the ability to exchange with other RuneScape players, which means that you have to find everything yourself, and no access to MTX, to allow a game like osrs in which it takes you so long to get levels, limiting yourself causes it to require much longer which in my view, unless you've got a lot and I mean a good deal of spare time, osrs is better as a regular account. Rs3 has considerably faster leveling system as stated before, and even indirect MTX with things like silver hawk boots makes coaching agility (among the slower abilities ) into a joke, actually wearing those boots provide you 99 by not even training the skill.

That is why in my estimation, rs3 is much better played as an Ironman, of course it might be better to start as a normal account to learn everything and possibly make enough money to buy old school rs gold pay for membership with in sport gp. At the close of the day however you're the one who determines what you like and both games have a free to perform option available so try out both, set a goal of completing 10 free to play quests or something and watch which you liked better.