The games are still tied to the console, but it seems that this is going to change with the next update (where it will be possible to use a single account for both WiiU and 3DS)

Nintendo is still behind Sony and MS on online services, but at least you don´t have to pay any extra to play your games online. They don´t have a trophy/achievement system - I personally don´t like them - but some games have online rankings and the few games with online play work really well. I was able to play Wii Sports Club, Tekken Tag Tournment and Fifa online with a very very limited 256k internet. That would be impossible with any Ms or Sony games.

I never used voice chat (the only game I have now that supports it is Call of Duty).

The friend system is simple and very easy to use. Miiverse is great, some games use it in clever ways, like Zelda and Nintendoland. WiiU owners seems to really enjoy it (myself included), you can share images and art. There´s also a tool to communicate with your friends using video

I won´t do like the others and try to convince you to buy or not to buy one, but I´ve got mine in 2012 one month after launch and I really don´t regret buying it. Having a lot of fun with its exclusive games ( I play A LOT with my friends and family on local play) and right now there are a lot of attractive and cheap bundles.

Same for me, playing online is not nearly half as fun as playing local with friends/family. In this sense I´m glad I´ve got the WiiU. Last New Years Eve there were 34 people at home (most family and a few friends). The device was on from 09 pm to 04 am, people playing Just Dance 4, Nintendoland, Sonic Racing, Mario, Tekken. I already had some Wiimotes and Nunchucks, so it was a blast!

Voice chat also supported in Monster Hunter 3 Ultimate. Never used it )).
Miiverse is great. It has a very different feeling then usual gamechats/forums and it makes it espesially good.

If your questions are about how the online and voice chat support is for games like Mario Kart 8 and Smash Bros, then I suggest you ask again when those games come out.

Anyway, I don't have any personal experience with voice chat on the Wii U. ...or with online play, for that matter. Most of Nintendo's first-party offerings at this time don't support it, though Mario Kart and Smash Bros certainly will.

Digital purchases are tied to an account, which in turn is tied to the system. If your console spontaneously combusts, you can call Nintendo and tell them to fix it and they'll recover your account for use on a new system.

Just do a Firmware update to your Wii U, problem solved. (the newest firmware)

If you are even considering buying the Wii U then you already want It. Go buy one now because probably later down the line you will end up with one anyway and don't listen to all the trash on the net with people rubbishing the system. The system Is very good and the games are glorious In HD.

It's selling more then the PS4:

http://gamrconnect.vgchartz.com/thread.php?id=173373

COD online is superior on WiiU if you have a friend coming over because of the option to play on the gamepad and one one the TV. COD experience is actually pretty good on WiiU if you want to play team deathmatch or free for all...... the other games option suffer from smaller install base.... 

Nintendo hasn't made any game that offer online multiplayer yet.....MK8 and super smash bros U will be the first two that will support online multiplayer.

Other notable are Monster Hunter 3, Sonic All-star racing

Apparently Warriors Orochi 3 Hyper as good COOP online but the games is not great.

For the record Wii sports club online sucks...... very limited and basic. The four player bowling is alright but these online option suffer from lack of variety and options.