We are traveling from Budapest to Ljubljana this spring. Hungarian Rail offers a direct train daily. It needs to be booked directly with them and the tickets need to be picked up in Hungary. Any experience with this route or carrier?
I haven't booked on the Hungarian web site, but it's looked pretty functional for several years. I assume that you already saw tips at http://www.seat61.com/websites/mav-start.htm. It's also fine to wait and buy tickets in this or another train station, if you don't care about a possible 20-euro price difference.
My experience has been that the Hungarian rail service, MAV, by and large is punctional, clean and efficient. Their web site could use a lot of improvement.