Well...
I love PPC Geeks - everyone here is... well a geek. We tinker with our phones and spend stupid amounts of time playing with settings. I see all the guys on XDA and here on PPCGeeks kind of slowly closing up shop and moving to the Android platform. Fact of the matter is the world of tweaking will live on but it will take time to understand what is and what is not possible. Never underestimate the power of the desire to tweak
With that stated I have officially moved to WP7 and to be honest I couldn't be more happier. Why? It's simple. For me tweaking was about getting better performance, better experience, more customization. WP7 is offering those things to me - it's just in a bit of a more controlled sandbox. I can change my theme, background color, and most importantly my LiveTiles to be what I want to see.
As Geeks we have a tad bit of arrogance - we want to know everything about a particular phone... we want to have the ability to hack and unlock its secrets... simple fact is the new WP7 phones world the tweaking community goes back to square A.) ... that's a hard thing to take lying down

Trust me... I realize this.
I also became such a die hard fan I recommended Windows 6.5 devices to my family and friends and alienated them further away from me only to turn off technology in general... sure WM was great for tweaking... sure Android is too but the problem is to GET the tweaks and WORK things out takes time and energy and most of all you break a lot of things in your pursuit.
With all that stated here's why I love my WP7 device:
1. XNA and Silverlight development... the single reason why Microsoft's marketplace will continue to grow a a blistering speed (5,000 apps in the first 60 days?) Developers can now develop against argueably the worlds most popular gaming system and a phone at the same time...
2. The UI... it's faster on all accounts... not just in speed - in overall accessibility to the things I look at all the time. It's clear, concise, and there's no fiddling around necessary.
3. Cloud - ZunePass, Xbox Live, and soon to be Skydrive integration... I think Microsoft will have the most consistent cloud offering of the bunch - they just know how to do it and they have the most extensible platform out of all the players.
4. Reading Email... it's missing some key features IMHO like threading of messages but the layout, look and feel of email on WP7 is far superior to all other platforms bar none. I'm a business user and Exchange is on the backend - it runs it like a dream.
5. UPGRADEABILITY... this has me excited the most - I can depend on Microsoft releasing updates. I know CCP is coming and they'll have it fairly fast. I know there'll be a app switcher and some type of tombstoning multitasking like iOS. I know Microsoft is not sleeping at the wheel and the nice thing is I can make requests on what I would like to see changed and because of the faster update cycle I know my change requests have a high possiblity of being answered.
If you haven't given WP7 a try do yourself a favor and check it out.