I'll take a shot at this. To give you some perspective, I have a good computer background, build my own computers and look to push the limits (jailbreak,root,etc) on my phones the moment I get them. Up until last fall I was using a combination of iPad/iPhone/Macbook Pro (w/ W7 bootcamp) and briefly picked up a GS3 to see what the fuss was all about. I quickly got sick of TouchWiz and running CM10.1 and the monthly builds, but still wasn't too happy with it (granted, it was my backup phone at the time, so I wasn't too worried about it). I've always really liked Microsoft, but Vista was a disaster so I went to Apple for a time but found myself missing the customizability of Windows (registry tweaks, etc). Fast forward to fall 2012, and I decided to go long Microsoft: new desktop, new htpc, Surface RT, WP8 and MSFT stock (always wishing for it to do better). It was a rough stretch in the beginning, the app store was pretty barren, but it's really picked up steam, and with the exception of one highly specialized professional application I use, I could not be happier with the decision. The only thing I now use my iPad for is to order seamless (when not close to a computer) and I haven't used my GS3 for anything other than downloading Jay-Z's new album in months.
Originally Posted by foolishfocus
With that said, here's my attempt to answer you particular questions
1. Gmail: Just know google has pretty much done whatever they can to screw WP over, but you can still use gmail. For the time being, you probably can't get push notifications due to Google taking away support for exchange active sync on free gmail accounts, but you will get the emails. This is how i had it set up until May, before biting the bullet and switching to Outlook.com (which I highly recommend). All email to my gmail now auto forwards to outlook, so I don't miss anything as I switch over.
2. School outlook: I assume this means your school uses Exchange Server for their email, if so you shouldn't have any problems.
3. Facebook / Instagram: Facebook completely redid the program and is now out of beta, and it works great. Instagram is a no-go at this point, but only because they refuse to develop for WP (founder hated his internship at MSFT apparently). That said, the Instance application is awesome, I use it all the time and it has nearly all the functionality of Instagram.
4. Pulse App: I don't believe it is on WP, but I don't use it so am not certain. That said, you can usually find great third party alternatives to whatever you were originally looking for.
5. PNC / Fidelity: Fidelity has an application (Fidelity Investments), PNC does not appear to offer an application. I dont have PNC so I can't really try the functionality of the mobile website. Chase and BofA have apps, so if either of those are convenient for you, you could always start to move over to one of those.
6. Google Maps: No support from Google, but gMaps Pro has google maps, turn by turn and latitude. Here Drive+ (for L92x/L810/L82x/L620) and Here Drive (L52x/L720/non-nokia phones) works great as Nokia owns the mapping company behind a significant number of gps handsets. Here Drive+ will be available as a paid upgrade soon for all windows phone
7. Youtube: Metrotube is arguably a better youtube app than anything google has put out. That said, if you like official apps, Microsoft and Google are working on a truly official app and it should be out soon (Microsoft released their own earlier this year, and it was great, but Google sued them).
Overall, I think you'll find yourself pretty satisfied with WP. With the W8.1, RT8.1, WP8.1 and Xbox One launches, you should see all the platforms come even closer together with a common link through Skydrive and Azure.
Hope this helped