I read this thread a few months back. I bought an ECHO 620P 2 months ago and 2 weeks ago I bought an ECHO 501P. Just some observations from the two... The 601 is 20% more cc, however, I think it has 50% faster cutting ability. The 620 is a real pro saw. I say that cause it feels right in between my Stihl 034 and my 441 Magnum... The 501P,,, well it is ok, but it seems much less like a "pro" saw, kind of like the Stihl 026 is a pro saw ,, but like the bottom end of a pro saw. I did time a few cuts .. The 034 , with a not so good chain but an ash 14"? in 18 sec. avr. the ECHO 620 did it in about 15 sec. and the Stihll 441 took about 12 sec. avr. My 501 would be about 20 seconds or so from the ash I have been cutting with it. The 501P might be a "pro " saw , but it is a beginners pro saw. It is about on par with my Stihl 026 , but the 026 has more torque , the 501 is likley not seated real well yet. It does seem to do best with high RPM's . This could be cause it is not broke in yet all the way. My 026 is a slower machine but has more torque. The 026 does have a crank case leak, but does not seem to matter when cutting.