I have been having good success as well, What i do is buy USD->BTC->LTC->Alt coins (i have a profitability calculator i made)->BTC->USD.

The only problem is trades are not happening instantly on cryptsy and I have no where else to turn so my profits have taken a hit (as we speak i have multiple XPM coins waiting to be traded back into BTC for the last 2hours)

I wish I had funding to knock cryptsy over and do my own site. Also I believe stagnation of coins comes the markets being open 24/7.