I began also with french defence, mainly because in old times als 1.e4 player I had always difficulties against it. 
Unfortunately I had also problems with black playing the french. At the time I switched to closed openings with white I also changed my repertoire with black and now play Caro-kann defence and Qd6 Scandinvian and value the reliability of these defences, which I always missed in the french. Somehow in every system I had the feeling that I stood very close to defeat from the very beginning and I had to use tactics to hold the position.
I come back to the french from time to time, because it produces very very interesting positions and it offers almost always chances for counter attack - however in most cases for me it´s the rubinstein fort knox. 
And I´m not so sure, if one can speak of the french in case of fort knox, because pawn structures resemble more the caro-kann and scandinavian - but  at least it´s a french beginning. 

What I consider as a huge disadvantage of the french is that it affords knowing a lot of opening and middlegame theory - may be more theory  a sicilian player needs to know.  If you can play hedgehog structures the sicilian world is open to you. As a french player you have to master isolani positions; backward pawns; closed pawn chains and not seldom everything during one game.  
In addition it´s not that bad if you know how to repulse mating attacks and you have nerves of steel. I can´t remember a single game, in which my king was really safe. 

Teaching youngsters I nowadays very seldom recommend the french. 
With regard to the practical chances in OTB games I consider the french behind 1...e5; sicilian, Caro-Kann and since the birth of the
Qd6 scandinavian only the fifth best choice in defending against 1.e4.

I´m sure french players disagree and defend "their" french right to the last cartridge One reason for me not to play 1.e4 anymore


greetings

Gilmour

Are French Defence player's attitudes any different than long-term devotees of other defences?  I think you'd get similar feelings from anyone whose played an opening for a few years with decent results.