I mine QRK - simply because I get some every now and then.
Tried J-coin for a day (it's first day) and got nothing, would of thought getting in early would do, but no.
Like you said, primes are out of the question as well.
as for memory coin - i just think it looks pants, and may be restarted due to it being an experiment, so i'm staying clear.
If quarks get to difficult I'll move back to pool mining YACs.
K.
thanks, yes, i'm with you on this for now. CPU's left on quarks for now, like you say about a couple of blocks per day roll in. Just about covers the power i guess hopefully may appreciate over time. The diff readjust seem very fast, it fluctuates with every info i pull from the wallet.