I know the MS500 series were good receivers, but they had their problems as well. I had 3 of them before I got one that worked OK. I had problems with the dish going for walkies across the Clarke belt when the receiver was switched off and the Pace favourite of the Power supply blowing.
I have now had my Echostar for 10 months and have used Irdeto, Viacces and Astons cams in it. OK, I've had problems with it but it seems that nowadays, no new product is 100% perfect when it is released.
I still find the Echostar to be the most comprehensive receiver available for digital reception with the bonus of Analogue too. I have had experience of Nokia (9200 and 9602), Humax F1 and Manhatten 2500. Add the Ad3000 editor to your system and you've got a very comprehensive system.
One thing that has made my Echostar more reliable is to add a PC fan to the top of the case, connected to the 12v supply. Now I no longer suffer from cards melting or the case getting hot.
Regards
Fastback