To make a long story short, they've been making it very hard to do things like changing domain ownership, changing contact information, transfering a domain, etc etc. I genuinely think their policy is to make things as difficult as possible to discourage their customers to make changes. The only thing that is very easy to do is (surprise, surprise) make payments.
I've been moving all my domains to Gandi too - I've been using them for about two years now and they've been extremely easy to deal with. I'll be very happy when the last of my domains will be gone from NSI.