actually a very large percentage compared to overall units. it was several hundreds of thousands of units.
Not to argue that Apple didn't have wifi issues, they DID, and probably as high or even higher a percentage than TFPs have. But you do realize that even if it was 500,000 units with issues, that's less than 1% of total units sold? Even if a million units had problems we're still talking a couple percent. Hell the iPad 3 is estimated to sell a million units the first day of sales.
It's very easy to get a skewed sense of proportion looking at forums. We see what seems like a lot of people here with WiFi issues and it makes it feel like the TFP has a lot of Wifi issues overall.
First, the people here are the exception, not the rule when it comes to what we do with our devices, how hard we push them and how much we know about the specifics of their functions. People here know which apps are best to use to test the wifi connections, they stress test the wifi to see how much it drops off at what distances, they try and use BT/WIFI/GPS in different combinations to see what effects what, etc. We're the 10%ers (if not 1%ers), the other 90% of TFP owners take their tablet, do some web browsing, watch a movie on their bed 10 feet from the router on their desk and love it. So we notice if there's even a small variation from ideal; and of course report it to try and fix it or to see if we just have a bad unit and need an RMA or whatever.
The second issue relates to the first in that even if there are a large percentage of TFPs with issues unreported by the 90% it's because the issues we are reporting aren't really issues for a vast majority of users. A weak wifi normally doesn't matter when your router is no more than 20 feet from any point in your apartment. What we consider dealbreakers many if not most never even notice. Which isn't to say the issue doesn't exist just that we may be emphasizing it's importance based on our XDA perceptions.
Finally there's the vocal minority issue. If you look at all the Wifi issues threads here and even on the apple forums and such I think you'd find that the actual number of people reporting problems is far less than you'd guess just based on perception reading the forum. It feels like a lot of people but I'm guessing here on XDA there's probably been less than 100 people that have specifically reported wifi issues that are major problems. But those 100 people speak up and loudly (as well they should at least on their own specific problem). Most prime owners that don't have issues never find this forum and never post about their lack of problems.