Dear @daveyf : A contender?. Well today almost any LOMC cartridge is a real contender, there are not a lot of differences between cartridges and cartridge designs. Same type of coils, cantilevers, stylus shapes or body build materials. Are so similars. yes exist differences but not day and nigth.
Air Tigth are designed and manufactured by My Sonic Labs ( former Entré people. ) that are really good cartridge experts.
Its internal impedance of the PC-7 is 7 ohms still a low one if we think that Benz Micro goes around 18 ohms and are very good too. So don't worry about.
Btw, @jeff1225 , you can get a second hand Shelter 7000. The 901 is not up to today quality permormace levels.
regards and enjoy the MUSIC NOT DISTORTIONS,
R.