There are a number of companies and they are all pretty much the same. We’ve done two of these with two different companies, one was Legenda, the other I just don’t remember.
I am going to suggest that with such little time you might want to do something else. Most of the lights can be seen from river embankment. This for instance had to have been taken from the Pest embankment about 30 feet from a nice café. https://upload.wikimedia.org/wikipedia/commons/6/69/Buda_Castle_by_night_2.jpg
If I knew where you were staying I could do better, but in general you might want to get a 24 Travel Card at one of the metro stations and then do the trams. They make excellent HOHO busses with much more character and charm.
In general you would take the 47/49 tram from Deak Ferenc ter past the Great Synagogue to Market Hall.
Go up to the second floor and look at the Hungarian trinkets, then the #2 Tram along the Danube Embankment to the Chain Bridge.
Then walk across the bridge and take the funicular to the Buda Castle. Spend an hour, then back down.
Now the #19/41 Tram north to Margaret Island Bridge. Get off at Batthyány tér if you just want to stand and look at the Parliament. Otherwise on to the Margaret Island Bridge where you board the #4/6 Tram back across the Danube.
The first stop on the Pest side of the river and a very short walk will take you to the #2 Tram that circles the Parliament Building.
Get off after going past the Parliament and then see the magnificent government buildings, banks and embassies as you walk through Szabadság tér to the Cathedral.
From the Cathedral to the end of Andrassy ut and walk up Andrassy ut to the Opera House, now board the M1 metro to Hero’s Square.
Its dinner time so walk over to Paprika Vendéglő (have a reservation).
Now take the M1 metro back down Andrassy ut to Vörösmarty tér, then a short walk to the embankment to see the lights, have a glass of wine in one of the restaurants along the embankment or on Vaci utca (the tourist street one block in from the river). Maybe go to Fat Mo's.