Recent reviews by Nex

Honestly I just got this pack for the capybaras, was not disappointed.

These days you see people all over the internet complaining about the lack of new content and generally being very negative, but don't let that discourage you if you're considering getting into RDO. I'm 200 hours into this game and not even close to being tired of it. I haven't even maxed out all the roles or bought all the horses and weapon upgrades I want yet. My advice is to take it slow and enjoy every second of the game. Of course I wouldn't mind new content myself, but I don't think there's a true reason why you shouldn't play (unless a beautiful, immersive cowboy/outlaw game isn't your cup of tea, but then I don't know why you'd be here in the first place lol).
Some say griefers and hackers/modders have ruined their experience, but I haven't met any hackers personally, and griefers are just an occasional nuisance that is easily avoidable by switching to a different lobby. Sometimes I just ride around and hunt, and forget that I'm even playing an online game. I can't vouch for everyone, though, because I've heard that it differs greatly depending on which servers you play on (for reference, I'm in the EU).
But yeah, I'd say go and have a try yourself. If you enjoyed single player I think you'll definitely like online as well. The map may be the same but the content is quite different and there are fun activities to get into for all kinds of playstyles.