So I'm coming back into the game and primarily enjoy PvP with a splash of PvE content. I have a max level defensive guardian and was wondering if this class is currently in a good place for PvP or if I should perhaps level up another character. What are peoples thoughts on tanking guardians at the moment?

Latest video card drivers? Latest HDD firmware? What sound card? Latest drivers? What mother board? Latest drivers? Wireless or Ethernet connection? Latest drivers for the network card? Background processes running? Virus/Security software been disabled to test? Have you tried to partition your drive (or use a second drive) and test on a known good operating system? Version of windows? Updated to the latest build? There are many factors your post does not take into consideration. Not sure I could say your issues are BioWares fault but I'm sure if you submitted a ticket with the appropriate information they would be willing to assist you.

I'd say the low level flashpoint mechanics better than most low level dungeons for MMO's. By the end of the third flashpoint (lv 21) you've seen adds to pickup, adds to avoid, "fire", knockbacks and aggro resets. Not sure what more you want from low level flashpoints designed to teach people new to MMO's about the game...

Your light/dark has no bearing on what companions think, only there affection rating does. Now, some companions, while actively with you will gain/lose affection when you make some (not all) dark/light side choices. If they like the choice is more based on the choice then if it's light or dark though. My current companion has disliked most of my dark side choices but has also really liked a few dark side choices.

Lots of them out there. Commendations and synthweaving will even give you mod-able ones you can use right through end game.

I found that I needed to fully close the game client and then log back in to receive the emails.

Not sure about point 2 (I'm not in the EU) but as for point #1 - I thought communication from Bioware throughout everything has been phenomenal. Forums, twitter, facebook, fansite summits and conventions have all been used liberally to provide a constant stream of communication for a long time. Aside from having a live feed of the developer offices I'm not sure there is more they can do. We do have a grace period now (48 hours)... I think it looks really good on BioWare to take the community feedback to heart. Maintenance is unavoidable, especially during a launch. I think it's good that BioWare has chosen non-peak periods to do this and even communicated the times to us in advance for the EGA week. My only hope here is that the time to perform this maintenance reduces as time goes on.