i didnt use MODs for a very long time, my 99,9% online flying (and i fly only online) is COOP in the VOW. VOW is 4.09 default (unfortutnalty 4.10 wasnt released before the actual run of it

).
VOW is dieing unfortunatly.....for whatever reason (missions are biased, bad planeset, bad missions - the typical online war complain stuff i guess , and sure, the MODs)
and COOP online wars a rare nowadays

so, to fly the dogfightservers (man, i am so fast boored to hell on these.......) most populated in the HL, you are forced to have a MOD.
and its true, nowadays they are easy to use , huge download

, but easy to install and use.
but for me personaly they bring nothing realy new. They are just needed to be able to join.
anyway, there are here and will stay . Thats ok.
and the most servers will stay 4.09 till "their" MODs are able to run at 4.10 IMHO !