I've been playing my Wii a little and had it online for a brief moment too, so I want to give some impressions.
Now, I only have Wii Sports and Wii Sports Resort for it, and I was pleasently surprised by WSR and the M+. Though it should be noted that I was never a fan of Wii Sports, so expectations were low. Anyway, having played WSR for a bit, I found archery to be quite entertaining, with basketball and swordfighting trailing shortly behind it. Still though, it's only a minigame collection, so I'll need some more games soon. Hopefully my budget won't be too strained.
The build quality seems nice so far, quite sturdy, both in controller and console (though I'm absolutely not a fan of the powerbrick). But seeing as the Wii is used (only slightly, but still), I came across battery issues right from the get go, which sucks immenselsy for me, as someone who likes Sony's system of charging the controller. I suppose I'll need rechargeable batteries to compensate.
The Wii interface is a bit confusing though. Does everything need a dedicated space on there, as opposed to having subsections? If I had a channel called "Demos" which would store all my demos, I'd be happy, but there is a channel for every demo O_o
Also, I appreciate the sentiment of telling me how I or someone else playing on my Wii did at WSR, but whoever thought I would want a letter for every fucking achievement should be taken out back and shot. Seriously. Not only is it confusing to try and make any sense of, but it is almost completely unnecessary.
I do like that Nintendo have shared the options-interface between the Wii and DSi though (don't know about DS, but it's that way for DSi), nice move.
Trying to go online and shop is a small pain in the ass though. There is no basic overview of the content. Why do I have to use the search options in order to get an overview of all games on the WiiWare? Why can't I just browse by a category? I won't rush through it next time 
Also, the downloading sucks. I can accept that there is no form of background downloading (though why we can't at least keep surfing for titles to download and maybe put in queue is beyond me), but why not have a tolerable download screen at least? I'm fine looking at Mario, but the sound is horrible. If your download screen makes me actively want to turn away from the Wii, the download screen is not good enough Nintendo.
Now, despite my bitching, these issues should be rather insignificant when all is said and done. Now I just need me some games to play, and I am hoping to find Metroid Prime Trilogy as my first game.
