I was planning to play SI and get IA as my alt. When Beta came I created only IA toon to see if it's worth to have this class as an alt and to avoid spoilers for SI so I can enjoy it in full when the game will be released...
And, well, I felt in love with IA from the very first dialog - I made it my main when SWTOR released and I really enjoy playing this class, forgot about SI
Yeah, sure, there are some downtimes, sometimes I think that some part of the story could be done in a bit different way, or maybe they should be a bit deeper - but in overall, it's just great and very involving
I got a few alts, but so far, no other class story can be a match IA for me