I would recommend again getting both. Back issues of the audio critic are $29.95 ACTUAl mag issues.
Back issues of SP are in pdf format on a CDR ($27 shipped). Both are very nice to read! They are 180 degrees out of phase! SP is a bunch of articles written by absolute DIYers, tinkerers, and is full of SETs, PP amps, tube amps, speakers etc.
The audio critic is a serious look at the "high end audio industry", you know hte ones that look down on horn speakers, and is a wholly rational look at audiophilia. Very different points of view, and both equally nice to read.
Recommend both sets of back issues. Best $60 or so you'll spend in audio.
-akhilesh