I picked some last year and did a couple of experimental brews. The drawbacks are that, although you may have a rough idea of which hops were grown in the area, these hops will not be representative of that variety. All the hops we know and love are reproduced by cuttings or rhizomes to retain the character of the parent plant.
You won't know the AA%age, in my experience it was very low, if I was to use them again I would vastly increase the bittering amount (think kilos instead of grams). They may be ok just used as aroma hops, but I didn't try that.
I was disappointed with both brews I made with them, I used significantly more in the 2nd brew, but both had hardly any hop flavour; just a grassy smell.
Where I live they are growing absolutely everywhere when you start looking for them, but I wouldn't waste my time again. They look much nicer growing where they are rather than in my beer.
1st week in september (wild hops may need longer) , is harvest time if you want to try them. Wait until they start to go a little brown, dried is best, but can be used fresh (I did). They also carry a lot of bugs with them, so try to give them a bit of a shake or gentle wash with cold water.
If you have room to grow them, rhizomes of known varieties are cheap, I think they have to be planted before 1st frost.