Soooo, I'm supposed to be taking a break from the computer. But, my DIY PK2 came in!
The sound definitely depends on the foams. Without any foams they sounded very odd indeed, with the stock foams it was better.. but I found the highs slightly muffled. Moved to some thinner foams from a pair of sansa stock buds and cut them into donut foams. These are the clear winners. I think differences in the foams could be attributed to some of the differences in impressions on these.
With the donut foams I am very impressed with the sound. They don't beat my portapros on sound, but they come closer than I believed they would. They certainly are more portable than the portapros!
These will be my new go-to portable set, replacing my portapros. I think I might try to order 4 more sets, 2 to give as gifts and 2 to keep as spares
TL;DR - If you have small ears and need a truly portable set of headphones.. This is definitely the best budget option, if not the best option period. Buy a set.