I doubt we will see a Wifi DX anytime soon. I have the new KDXG and I can attest that the 3G sucks if you live in a marginal area of coverage, especially if you have AT&T. I cannot download large books (over 10 MB) even with 3 bars. However, using WiFi via my iPod touch I can quickly download even larger books. So i would say that WiFi is definitely faster and more reliable if you are in a marginal coverage area.