Hello!

[Titans]

You can gain 99 leves. If you have that many and time, you can do them all in one day. You can hold a total of 16 leves. After which you can go back and pick from the remaining leves of the 99 you had to choice. Grand companies or for the most part similar. There are some differences but not much from what I can see.
Unfortunately I play on a different server. It's a mix community, but you can find English speakers. Excalibur is my server

[Urthdigger]

You can hold a total of 16 leves.

This isn't QUITE right. You can hold 8 regional leves (battlecraft, fieldcraft, or faction leves) at one time, PLUS 8 local leves (Crafting leves). Company leves also cut into your stock of leves, but these are started immediately as soon as you pick them up (They're also accepted AT the camp. Each region has one level 30 camp with company leves, and one level 40 camp with company leves, so don't worry about them until then).