Wmt1, I absolutely believe you and I absolutely think I could be doing something wrong cause you are the train expert. So, I went back this morning and looked again. For context, yesterday I started looking on the MAV site first. I picked the 09:40 because it provided the most sleep and still got me to Budapest for lunch. But it does take about 10 minutes longer. And, the price on MAV, not the cheapest, was fine.
This morning I looked and here are the choices I get on my laptop from the two ticket agencies.
08:40
MAV 13€ + 2€ (no cancelation, that train only)
OBB 24€ + 3€ (cancelation not possible / valid Mon 15 June 8:40 – 11:26 / transports that cannot be changed EC141)
09:40
MAV 17€ + 2€ (no cancelation, that train only)
OBB 52,70€ + 3€ (cancelation free of charge until 14 June / Valid from 15 Juen till 16 June / Free choice of means of transport)
10:42 (to Budapest Kelenfold, not great, but okay)
MAV 15€ + 2€ (no cancelation, that train only)
OBB 24€ + 3€ (cancelation free of charge until 14 June / Valid from 15 Juen till 16 June / Free choice of means of transport)
So, if I am doing it correctly the cheap tickets from OBB are gone for the 09:40 train. But in all fairness, generally speaking, the starting price on OBB is 27€ with a seat vs 17€ with a seat on MAV. That makes OBB somewhat more competitive.
Oh, the seat reservation. No you dont have to. But I have been on that route several times over the years. Sometimes all the way to Vienna, sometimes just Budapest to Gyor to Budapest. Not always, but a few times the train has been pretty full. I have watched someone get displaced more than once when people with reservations boarded and I have had to put up with the dozen backpackers standing in the asile swinging their backpacks around and into the people sitting ... which is why First Class isnt a terrible idea. All three trains above are 29€ (including the seat) with MAV in First Class.