rough, i dont have much experience so take it with a grain of salt...
the expierence is cool.. it is well organzied, desolate, pretty course...
it is a tough course. i have only 3 50k's and two 50 milers. both 50 milers have been the pct, so i dont have much to compare to, and the 50k's i have done are easier ones.. lake hodges 50k twice and the high desert 50k once. never done a road marathon.
the pct takes its toll... first 13 miles are mostly uphill. its dry down there, and in May, the weather can be brutally hot.
i think avalon is easier, but havent done it and dont know for sure. it is more expensive and more of a pain in the ass with the logistics of getting out there.
fuck it, do them both. run the high desert 50k in december, avalon 50 miler in january, then the pct 50 in may...