The benefits of OSRS for me aren't really gameplay-related; it has UI scaling (nice for my 4K display), runs on iOS (gives my iPad purpose), and although it doesn't seemingly affect me directly, it has a larger player base. I don't particularly like how there's a few BiS content areas for skills though (WT for Firemaking, Motherload mine for mining, NMZ for meele; the last one being a terrible cheap implementation).

RS3 however is just overall more engaging to me.

I'm relatively low-level in RS3, but here's some of my feedback:

• Getting around the world at a low-level is a big PITA on OSRS; although I suppose it does make getting teleports feel rewarding
• The toolbelt on RS3 is nice
• Pest Control is my favorite minigame; can always play it on OSRS, but I have yet to see anyone do it on RS3 (apparently some people only do it when it's on spotlight?)
• EoC is decent. I'm not sure if people typically lump weapon diversity in with EoC, but I really like that I can use different weapons, and that type advantages are more prominent (using a 2H sword, mace other than Ancient, or any spear below Zammy in OSRS is basically unheard of; scimitars are BiS for most meele). Being able to cast abilities also makes combat more interesting