Not likely. A single site (or it's sector) could have maybe been bogged down by users at the exact time you were there, but as a market, it will take some time (if ever) for it to bog down. It's a larger slice of spectrum, and can accommodate more traffic. Like Robert mentioned; the site probably didn't have it a backhaul upgraded. Even 20mbps back in December would be slow on an unloaded sector. Spark is really fast, and should be in the 25-35 range, and peak in the mid-to-upper 50's. Then again, it all depends on signal, distance, users, etc..
Vince