WP7 > Maemo
Nokia obviously agrees because they are scraping Maemo in favour of WP7, although they'll still use MeeGo for low-end devices.
Maemo doesn't even exist anymore, even before this deal, so I don't get what you're saying. Also Nokia isn't going to do MeeGo at all, they
might release one single device with it, but they are pretty shakey on that. Right after the this deal, Nokia came forth and said they weren't exactly on good terms with Intel or AMD (two of the major forces behind MeeGo now that Nokia isn't in the picture)
For developers, WP7 is one of the best mobile platforms out there, if not the best once Microsoft fixes the stability issues and opens the phone for homebrewn applications... which I think will happen soon since http://www.winrumors.com/windows-phone-7-jailbreakers-working-with-microsoft-on-homebrew-support/ on homebrew support right now.
The reason MS is thinking about allowing homebrew is because they are going to lock the market like Apple did, which doesn't help you get developers at the start. MS sees homebrew as a way of having your cake and eating it too. If it actually comes to light as being allowed (given the restrictions MS is placing on app development, I honestly don't think it will, I think it is once again MS saying it to get support), I wouldn't at all be surprised when it is disallowed in the future. Though I definitely agree with you that MS needs to get the kinks out of their phones first. They released WP7 too soon, its lacking numerous features common, not just on smart phones, but regular phones too (such as the ability to set custom ringtones)
While Java and Objective-C are great programming languages (Android and iPhone) how can they compete with C# and the .Net libraries? and silverlight support, and XNA for games. I know that iPhone and Android are supported by Unity3D, so I understand game developers who develop for the iPhone/Android platform, but I figure Unity will publish WP7 support soon since WP7 natively supports the .Net/XNA libraries which makes it an ideal platform for creating games.
I created a small WP7 application a few weeks ago (scientific calculator with functions to do molecular calculations... I was bored in my Chemistry class) and the development process was absolutely brilliant. I just downloaded the WP7 development kit, created a new project in Visual Studio 2010 and probably spent more time having fun with the interface design than actually writing code. No searching for libraries, no coding headache, just creativity. ^_^ ... of course I don't have a WP7 phone so it was of no use to me, but developing it was great. I actually ended up re-writing it in PHP/Javascript and putting it on my website so I could use it on my phone.

I may be a little biased since I've hated the Java platform (for mobile apps) since I tried to write a J2ME application a year ago. The only thing I learned from that was how an aneurysm feels like. <_<
I know I shouldn't judge the Android java platform on that experience, but it's hardcoded into my brain that Java + Mobile = cthulu-like horror and despair. :cold: I'm sure the java platform for Android is easy to work with and all, but I just love the fact that I can port my Windows C# projects to WP7 with only minor changes to the code. (Since WP7 supports the .NET libraries)
Well, Java developers are a lot more commonplace than C# developers (I should note, as much as it pains me to admit: I agree with you that C# is better than Java, but I'll probably never do anything with it until the scourge that is Mono is killed off and replaced with something actually officially supported and released by MS --- which'll never happen). While you may see it as a joy to write for, WP7 is a complete new build from the ground up, breaking compatibility with apps from before, which didn't exactly win brownie points for windows mobile developers. It also isn't possible to port some things because of the restrictions MS has put in place (most obvious example: http://tech.fortune.cnn.com/2010/10/22/sorry-windows-phone-7-app-makers-the-camera’s-off-limits/, which many popular apps like Layar do -- multiple developers have cited things like this as why they can't port their app to WP7). Finally it's a logistical thing: porting to WP7 is costly, and the audience just isn't there or the uptake. Its a chicken-and-the-egg problem. Developers don't want to spend the time porting there without consumers, and consumers don't want to be there because there's no apps.
Of course Microsoft is trying to deal with the problem in their usual manner: http://www.pocketgamer.biz/r/PG.Biz/Windows+Phone+7/news.asp?c=21387 until they can get the biggest marketshare money can buy.
overall I think that the WP7 platform will conquer a large portion of the mobile developers out there, http://www.winrumors.com/anolyst-claims-windows-phone-7-will-be-the-fastest-growing-platform-in-2011/
That's a single anolyst, hardly a large group of experts (rather, from the article, just a singular "expert"). It doesn't seem to be the case either. We'll have to wait for the quarter's statistics to come out, but adoption seems to be pretty flat from what I'm seeing and reading.
This is further troubled by the fact that http://www.pcworld.com/article/207596/microsofts_windows_phone_7_no_tablets_for_you.html. Windows 7 proper is going to be their only offering on it. That's segmenting your developers and not something I'd say is a good move in the current market.