This is one deadly race.
But if any opponent has MM, you are dead. and i mean, a level 5 sorcerer true true faerie will have about 13 hp. meaning it will take a level 5 sorcerer/wizard of any race can put her below 0 hp with a single, never-miss three-shot magic missile. (3d4+3, average of 10.5 damage. close.) at worse case he needs two casting (and with two casting you can do it in level 3. 4d4+4 gets you an average of 14 damage.)
A level 3 wizard can kill her with 1 scorching ray if he hits. and if he hits, he can get her to -10 by that hit. (4d6. average of 12 damage.)

As far it is hard to hit this critter, every hit is deadly for it. the -6 con is a hard blow.
Also note, that due to size, some funny things can happen (tanglefoot bag? you drown.)
Risky to play, as far as it is good, you need skill and cunning (as a player) to survive.

But i would still raise LA to +3