I must say I'm quite impressed with the new stations, or at least the few that I managed to see. Especially Serdika 2 - it's bigger than I expected. Though I was more interested in the ruins around the station. I saw a lot of them when they were uncovered and I was worried that half of them would be destroyed or covered again. I could very easily picture someone deciding that the street on top is more important or that old ruins can't stand in the way of progress or something like that. And at most they would just use different coloured tiles to show where the walls were, like in Serdika 1. Thankfully, everything I saw is still there, though apparently work is still being done there. I hope they make it so that you can walk past some of it, not just look at it through glass windows. At least the part between the Presidency and the Council of Ministers looks like it's going to be that way. I'll wait until everything is complete before praising the people responsible, but so far I'm quite pleased. 
I think I've mentioned it before, I have no problem using my left hand to insert the ticket at the entrance. In fact, I don't think it ever occured to me to cross my right hand over my body for this. However, the problem I have is that sometimes the machine apparently has trouble reading the ticket. I often have to pull it out a little and reinsert it a couple of times. This could be quite annoying, especially if you're in a hurry and the train is coming. 
Also, welcome back to sunny, sunny Bulgaria :)