Click on the images to embiggen.
I thought I'd look at it using Wifi Analyzer.
I've done this in a few spots around the house with similar results. I haven't bothered to run any speed tests. Plenty of those already on the web. If I hold the Transformer Prime close to the wifi router with the front facing towards the router, the signal is about 5dB higher than when I turn it around with the back facing towards the router.
If great wifi range and performance is what you need, the Transformer Prime probably isn't for you.