The new mobile OS is on sale in Europe for some time now and untill now the feedback seems to be good, but I can't find any hard numbers.

Here is all I found: http://www.digitimes.com/news/a20101028PD206.html (HTC HD2 sold beyond expectation, HTC unprepared for "massively strong demand")

And one German news:

http://www.n-tv.de/technik/HTC-HD7-bei-O2-ausverkauft-article1817471.html (in German - Windows phone 7 off to a good start HTC HD7 sold out at O2 is the title, some notable things: HTC HD7 at least sold at the higher end of the 5 digit-area (about 80000 phones), German Telekom reports strong preorders for Samsung Omnia 7 and HTC 7 Mozart, Vodafone asked for a bigger shipment in order to meet bigger demand than expected, LG reported positive demand for the E900 7, Every manufacturerer expects at least 6 digit sales for the first Phone-7-quarter) 

http://translate.google.de/translate?js=n&prev=_t&hl=de&ie=UTF-8&layout=2&eotf=1&sl=de&tl=en&u=http%3A%2F%2Fwww.n-tv.de%2Ftechnik%2FHTC-HD7-bei-O2-ausverkauft-article1817471.html (Google translation)

What do you think? Could WP7 be a success like Android?

Sold out of all the phones I could see in my country, though I think only Vodafone stocks them.

I hope it's a success. The more successful it is the more support it'll get from devs.

In Germany sold out.

I Have a HTC 7 from O2, very good one.

i want a new Xbox... sick of this gen serious not even Reach is addictive anymore.

I think initial demand should be fine.  The issue is knowing how much was available to sell.  Did they stock for a big uptake or something more modest?  As ever the initial inventory and sales are the key to seeing what the success rate was really like.

i want this phone so bad!!!!

I am happy with my Android phone. And i was honestly expecting WP7 to flop

I want the Dell phone, but I'm not sure wtf Dell is doing, as they have provided ZERO info, so my backup to get on Nov 8th is going to be HTC HD7...that looks pretty sweet, and it is on T-Mobile, not lame ass AT&T.

http://www.microsoft.com/windowsphone/en-us/buy/7/phones.aspx

I'm getting HTC 7 Mozart very soon.