In this August, I took flights of IST-BUD-ARN.
(Reason ?, Probably very clear for members of this forum )

IST BUD MA205 0525 0620 737-500
BUD ARN MA764 1820 2030 737-600
class J (D)
fare 371 EUR

Business class seats are almost same as BA's one.
I feel slightly better than BA, bus very marginal.
Hot meal service is almost same as BA's Club Europe.

BUD airport is very small.
I took taxi to city center and enjoyed 3 hours sightseeing bus tour.
(1000-1300)

I tested thourgh baggage handling.
I intentionally arranged one through checkin baggage at IST.
Luckyly, I got the luggage at ARN peacefully.

Wifi hotspot service is available at BUD.
However, you need credit card and SMS capable roaming phone.
The hotspot service sends activation-code/password to your phone by SMS.

There are three lounges in BUD, but nothing sepcial, very minimal.