I sometimes buy directly from Craft Supplies and Berea. I really don't buy directly from PSI. But I do buy most of what I need from either Bill at Arizona Silhouette or Ryan at Woodturningz, and occasionally from Sheila at Pens of Color. I can heartily recommend each and every one of these places!
Whose kit you use for any particular pen should be based on your own needs. I mostly like kits from Craft Supplies and Berea. They are consistently of a high quality. But I also use some specific kits from PSI, and not just because they are cheap. My favorite slimline kit is a titanium gold from PSI. Use your own experience and buy the kits that meet your needs.
And Mark, it's OK to tell of your experiences with a particular kit, good or bad, like you did above, but lets leave it with that, allright?
Scott