had both, love them both. would quite happily own a pm8 again, but at the moment have 2x 05's and they just don't fail.
A lot depends on price for me, both of mine cost less than £120 each and for this sort of money you can't get any thing better.
Parts are getting harder to find, they do come up on here tho but shops don't have much.
A friend has every up going on his, and he has used it constantly for the last 4 years, he has had other markers in between but he has always gone back to the 05. just doesn't miss a beat.
Pm8's do feel nice, had pm's from 05ish and the pm8 does feel like the culmination of all that came before, nice cnc work, good grip.std parts are probibly easier to get, but i'd say not as many aftermarkert bits avalible.