Interesting.. Based on the above numbers, it seems more like a 3G router. Curious. Did you download the iSpot app to check the signal strength for the speed test? If not, do you recall what the color the 4G LED light indicator was on the router during the test?
Also, I was wondering if you contacted Clear customer service/tech support regarding your findings, as those seem slower than they should be? Based on some speed test comparisons of my own, i'm experiencing an average of a 19-25% increase in speed over AT&T with 3 bars present, a 42-56% increase with 4 consistent bars, and 73-81% increase with 5 bars of signal strength; the differences in %'s were based on selecting the default Canada server, or the closer Los Angeles server. The app I used is speedtestX HD (accurate?). Not sure how reliable it is, but it at least gave me a measuring stick to compare to your findings. I positioned the router in different areas to get the varying signal strength and ran two back to back tests on the two carriers to see what my results would be. Unfortunately, this was not the best controlled test, as i could only vary one control (the iSpot's signal strength by changing locations, I could not get the same matching variance with AT&T's signal strength, which was 4 bars on the the first test, 5 bars on the second test and 4 bars on the 3rd test. Each test was done within 20 feet of the router. With the best Clear 4G speed result (5 bars as shown by the iSpot app) yielding an 81% increase over AT&T's 3G 4 bars as shown on the iPad's top left readout. Doing some fuzzymath based on 1.4 mbps representing 3G, and adding 81% to that, I get a 2.5 mbps. That based on the validity of the free speed test app used to determine the speeds my ipad was seeing. In any case, it does not compute to a 4 fold increase as Clear advertises, however, I do notice greater speeds using the 4G router vs the internal 3G connection through AT&T. I'll see if I can conduct another test tomorrow, and share my personal findings. In the mean time, I would be curious to find out what the LED color was or the iSpot's signal strength was showing on your iPad app, as it does affect of the connection download from what I've seen.