The main fault is that they're something like 2/3 reviews. Nobody actually refers to a magazine to find out how good or otherwise a game is: they'll go to the Internet. The edge I always felt NGamer had over online coverage is that it had quality writing, interesting features, and pure entertainment. It obviously wasn't enough of an edge (yes yes, ho ho) to guarantee its survival, but if you're just going to give reviews that outline the features of a game without eliciting even a glimmer of a smile, you may as well make a website and do so in a timely fashion.
I guess the bottom line is that I don't think Switch Player's writing is very fun to read, whereas Ninty Fresh's is. It probably also benefits from the more staggered releases: I had a pile of SPs building up on my loo that I just hadn't read.