Or just be smart and uninstall Graal PC...
But in all seriousness, it depends on what community you're into. Era = young kids crying/trolling all day and you will pretty much be guaranteed to not get anywhere and will get no help; Zod = pretty fun, decent community that's fairly nice and helpful, actual content, fairly easy to grasp (if you actually try to) and a wiki; UN = laid back community, practically all player-based with content and events/mini games; N-Pulse as of now doesn't really have a whole lot of content, but they're making a come back. As far as Classic goes, I was never a fan of its original for PC, but they're definitely worth checking out. Or you could just play all of them and see which ones you like the most.

never forget the blaze bro. never forget

O boy

Classic.

Lets be real here...
 

Kingdoms:

'Cause it doesn't sound like a clown dropped his suitcase full of bike horns when you die.

Better than the other communities. lol

UN, or stroseria, when it comes out.

UN has a lot of content which may take a couple of hours to complete (to get the 13 hearts, level 3 sword and shield) which is quite varied.

Kingdoms is fun but ultimately repetitive.

Zodiac is a lovely playerworld, I would strongly recommend this too.

Zone is a fantastic server but you need a few players to fully appreciate the gaming experience.

classic is fun. Do all the quests.

comparing turds really

zod #1 turd

Zodiac or Era are probably your best bet.

well as a trial Era and Zodiac are the best since they don't have observer mode. Stupid Stefan wont work with UN to get it removed.

With gold it depends what you like.

Era is good for a modern gun themed server, it really repetitive though and if you don't spend hundreds of hours doing the same task over and over to earn enough money for a decent gun you get owned by other players.

Zodiac is ok but its grindfest. Before you can even start playing you need to work for like 2 million gold just to get an essence to play a race good at the class you use. If you play at level 60 as a human its hopeless. If you like games like WoW this might be the game for you.

Unholy Nation is fun to just jump into and play. Its more casual but fun. Quest for ~1-2 hours and you're even with everyone else.

With Classic PC you can do their quests but not much more since they're still UC.

Do quests for like 2 hours then you're even with

If you're into combat and PKing: UN

If you're into MMORPGs: Zodiac

For a hybrid: Era

If I still played Graal in any active way, I'd go with your vote.

My answer to the OP: If you try to legitimately play any server, you're going to want to figure out a way to make it where you have the most choices that appeal to you, secondly, find a community that you can enjoy being with, everything else should basically not exist. Otherwise what Googi said, if you want even, I can PM you a few different game sources you could explore for other games on.