I've used both and I say they're really good ships but I really cant decide on which is
actually better

L class is good with the 6" guns

Ok I've given the L a test run... its essentially half a Sirus... the point this boat becomes usable... ie. level 35 with the machine gun duel 6s... you won't be in it.

Word of caution.
If you mount 6" guns you will have little to no space for ammo.

oo thx guys i realy need thaty :) wooo i am happy lol ^^

Well,

The L (I've not used one I'm just looking at the numbers) Has:

3 x 75 space gun spots (Q: 4 x 53 / Tribal 4 x 64)
27 turning force (Q: 33 / Tribal: 24)
It has 2071 tonnes of ussable displacement (over than 500 more than the Tribal/Q get)
It has 73 engine space (same as the Tribal, the Q gets 61)

The L's inhernent defensive values are better balanced than any other RN DD (its HE defensive is 297 (4 less than the Tribal's), its AP value is joint highest (tied with the O) and its AAW rating is the best of any RN DD.

Essentailly, with 3 gun spots, this is a boat for people who're already able to get out of their DDs and into Crusiers. If you get this boat at the level it becomes avaliable to you, you're losing fire power, however once CL type guns appear with the 75 gun space you can mount any set of guns the Sirus can :)

Oh... it also has the largest T mount (at 40) in the RN until the Edinbourgh and the York :)

when you get above lvl 33 you can get double 6" guns which wreck havok from an L class.