Which client? (also, what does a mod selector do?)

Which client do you prefer? Ninjin? or Nova?
Is any of these "better" than the other? Why would you choose on over the other?

Also, what is a mod selector? How do we select mods? Does it change the client? Or its a program that we run? Is there an option for reconnecting to a dungeon? coz I really miss the dungeon reconnect of the old onurm client.

Welcome to MPGH?
Ninjin and Nova clients are both nearly identical, except that Ninjin added in the Realm-Eye feature, which allows you to look up someone on RealmEye through an in-game button. I think you have to alternate between two clients to toggle fullscreen/normal on Ninjin, and on Novaclient you can simply type in /fs to toggle the feature.
The mod selector (that I used way back, at least) was, well, a mod selector. Simply go down a checklist of what you want in your game and what you don't want, then play! And no, I don't think there are dungeon reconnects on either Ninjin or Nova. HOWEVER, you may want to check out a hexed client that was originally from the reconnect client, that's still a possibility.

Nova was a hexed client from i think 10.0 to 11.1 and ninjin was made from 11.1, so if it were me, I would rather ninjin's, otherwise certain things in game would be missing from view using a hexed version e.g. rock dragon. If its mods you are after, then yes they are practically the same. I only say nova is hexed because i have checked both clients against Jnoobs source codes, and the nova client does not match any of Jnoobs codes, folders, or file names, where as ninjins does.

Hexed means : "old" hacked client where the version was edited to let it connect to the game server.
Its a fast way to play when they update the game but it's not always enough.

Sometimes, if they add game content, its required to use a genuine hacked client.
If there is an updated hacked client, forget the hexed ones, as usually there is a REASON for the fressh one to exists.
And it certainly works better

If there is only hexed client :
- Maybe hexed one works fine. Everyone use hexed when an updated client isn't really needed.
- or... hexed is bugged and you wait for an updated hacked client