It really does. I'm in the same boat, just switched from a Nexus, never used iOS version, but I can tell you Android/iOS version is leaps and bounds better than WP8.
WP8 version isn't just "lacking", it's down right bug ridden. If you put an Android phone and WP8 phone side by side, 9 out of 10 times WP8 will pull down messages with a non-trivial delay.
The live tile does essentially nothing. In Android, if you open Whatsapp and go to the message list, but don't go into the actual tread, it will still be treated as unread, and the notification will remain in the notification area. If you swipe it away but don't read it, it will reappear in the notification area after a certain period of time to remind you, e.g. 30 minutes or something. In WP8, once you open the app, it's gone. I imagine the number bubble in iOS will also remain unless you actually read it.
Notifications are a total hit and miss, some times they come up, some times they don't at all, and you need to manually open the application to get it to pull messages, and then out of nowhere 30 notifications come jumping out and the phone doesn't even have enough time to stop between vibrations.
Then comes actual messaging. I have experienced more than enough times where the massage will not send, or at least appear that way with a ( / ) crossed out icon. I need to back out, i.e. close (not suspend by hitting "home"), of Whatsapp and re-open it to get it to send.
And sharing. This is probably more of a WP8 issue than a Whatsapp issue, I'm not sure. In Android, you can select "send picture", and choose images from practically any installed application that has images, i.e. Dropbox, Gallery, File Explorer, and god forbid even Skydrive (which is actually pretty nice on Android too, albeit a bit slow on loading content). But on WP8, you can't even attach images from MSFT's own SkyDrive, which is pretty sad.
But yeah, those are a few things I have complaints about.
I like the phone, but developer support is still lacking at the moment, that's a fact.
Edit: And if I'm not mistaken Whatsapp is not yet updated for WP8, which is probably what the leak was about. That might be the problem, time will tell. At the moment, it's terrible.