It looks like I might be the only Windows Phone user on the list, so let me chime in with my impressions.

I have T-Mobile right now – the plan I have with them is great since I chew through an insane amount of minutes each month, plus text messaging and a fair bit (but not more than 2GB) of data. The T-Mo network is very fast where it has service. The "but" in that sentence is based around "where it has service" - when my wife and I visit her family in Charlevoix I'm reduced to 2G (EDGE) data and she keeps 3G on her Verizon iPhone. I fully intend to switch to Verizon when my contract is up and their LTE service is a little more mature. LTE is scary fast – I've used it a ton on one of their MiFi hotspots – and offers several technical advantages over older 2G and 3G technologies, especially for CDMA networks.

As far as hardware goes, I've had a HTC Touch Pro2 (old school Windows Mobile), a HTC G2/Desire Z (Android) and now a Dell Venue Pro (Windows Phone 7.5). The Touch Pro was old Windows Mobile, and I think everyone knows how that went. Plus, that platform is dead dead dead. The G2 came running Android 2.2 and I immediately grabbed a 2.3 release from XDA Developers. I ended up running CyanogenMod 7.1 on it – I actually stopped using the phone at 7.1RC1 – and it worked pretty well with a few caveats. My battery life was never great – I had to put the phone on my desk to charge at about 2pm or so – and the stock firmware was dog slow. Once I got CM7 loaded it sped up quite a bit but I still ran into the occasional performance glitch – things like TweetDeck would just lock up for five or ten seconds before responding to touch input every couple of days. Bluetooth sound quality was excellent but the built-in Android bluetooth voice control was complete crap. No controls like the older iPhone voice actions – certainly nothing like Siri or voice-to-text. (You could trigger voice-to-text from certain input fields but not direct from your headset – pretty useless when you're driving.) The biggest software advantages were the Swype virtual keyboard (best ever, hands down) and the extensibility of Android. The biggest disadvantages are the general crappiness level of the stock non-Google Service applications. The internal Gmail client is excellent – however, the built in mail client doesn't have pinch-to-zoom, doesn't have search, barely has folder support, etc. Guess which one you're stuck using if you want Exchange or MSU Mail connectivity? There's a couple alternative programs – K9 Mail and TouchDown stick out in memory – but they have their own flaws, like not playing nice with the built in address book or crashing constantly. If you're lucky enough to have a phone with HTC Sense you get a replacement mail client that's excellent – except for the part where it dumps the bottom 80px of screen resolution for a clunky toolbar. Oh, and if you root your phone you lose the client.

I picked up a Venue Pro a couple of months ago and have been using it as my day-to-day phone since then. I've found the Metro interface to be intuitive, but it's definitely a love-it-or-hate-it thing – the user interface is unlike anything else on the market. I think its biggest flaw is it makes it difficult to select from a long list of apps. The phone supports some of the nice features that Android doesn't do well, like unified inboxes for email, as well as some features that neither Android or iOS do like contact "hubs". The phone organizes your data in these collections called "Hubs" and by default it ships with your standard ones like All People, All Photos, etc., but you can add your own groups. I've created a Family hub on mine that centralizes all the info from my family members and lets me get all their contact info, in addition to things like Facebook and Twitter updates, in one place as a separate stream from my normal Facebook/Twitter feed. The phone unifies Facebook and Twitter updates into one content stream (including photo postings if your FB friends allow that privacy setting) which is pretty cool to see. It also supports full Facebook contact download, like you can do on Android devices with Facebook installed, so if you have a friend with contact info on their profile you get access to that in your People hub's address book. (This can be switched off.) Biggest advantages to Windows Phone are the tight Exchange integration, overall fluidity (on par with iPhone in terms of speed), and (in my opinion) the very attractive interface. Biggest disadvantages are the paltry app selection, funky multitasking (it's a lot better with 7.5 but there's still quite a bit of ground to cover), and the occasional interface quirk. It's a very new platform and Microsoft is committed to it in a way that they never seemed to be with Windows Mobile. The phone does support pinch-to-zoom in email and important things like email search (and server-side search for Exchange) and there's a pretty good Google Voice client for it called GoVoice (which is essential for me because I rely on Google's voicemail-to-text transcripts) so an Android-to-WP transition is pretty easy. It also has a superb Bluetooth voice control system which isn't quite at Siri level but is easily the superior of the previous Apple voice control system. Android's voice control doesn't even compare. Voice dial works well, even in noisy environments, and handles contacts with multiple numbers easily. You can send text messages using voice-to-text without looking at the screen. You can also trigger Bing searches (though you have to look at the results manually) using voice. You can't change audio tracks but that's not a feature I found super useful on iOS anyways so that really doesn't matter to me for Bluetooth. You also can't send voice-to-email – Siri wins there.

Really the biggest flaws in the Windows Phone experience for me right now is the subpar camera module that Dell installed in the Venue Pro. I hear that the HTC and Samsung Windows Phones are much better in that regard, though. I would highly recommend Windows Phone or an iPhone 4S. If you're like me and need the maximum speed, you may want to try an Android on the Verizon LTE network, but honestly I'd wait for either a LTE-equipped iPhone 5 or a LTE-equipped Windows Phone. Oh, and I realized I forgot to address the Flash question, so here it is – Windows Phone also doesn't support flash. My G2 did support flash and I tried it a couple of times. I never ran into a website with something more complex than a video on it that wouldn't crash my Android's browser or become completely unusable. Videos lagged horribly. If you're thinking of running something like the vSphere flash-based web client or the VMware View console, you're better off getting a cheap dumbphone and a MiFi and then hauling around a netbook or something with you. Trust me.