My money is on Sch. 40 PVC, particularly if you will be planting or digging in the future. I also do not like having to fool around with hose barbs. I like the compression collars that accept 1/2" distribution tubing and glue into the PVC fittings. It takes a little muscle to force it in, but no tools are needed and I've yet to have one come loose.

Thanks for your comments. I too am a little nervouse about hose fittings particularly rusting away in an acidic soil. Do you have a compression collar fitting manufacturer that you have had success with?

The last time I did a system like that I used Rainbird, but there are a couple of other manufacturers out there (like DIG, Toro, and Orbit) who I'm sure are fine. Just make sure that you get the compression fittings and 1/2" poly from the same manufacturer as there are minor differences in tubing sizing that can cause problems if you mix brands. The only other advice is to also make sure to drain and blow out your system each fall: the one advantage of poly over PVC is that it is a little more resistant to freezing damage.