I was there for a night in April before switching to the castle Hilton.

Diamond guest, last minute booking, pretty full hotel so no upgrades.
Room, small, basic, clean, unmemorable.
Breakfast, quite good buffet and cooked to order options. If HGI is same price as a lesser breakfast hotel, no reason not to go HGI.
Location is just off main road - easy walking access but plenty quiet. If that works for you, location wise, go for it.

As a tourist, I prefer Buda to Pest, and the Hilton on the hill is quite nice and classy. Two totally different properties, options, and vibes of course. If you need a city hotel base that’s just a bed and a nice breakfast, HGI is fine if a good price.

Bonus area tip: make reservations and have a meal at https://retekbisztro.hu/