The wife and I only ever stay at non chain hotels.
I use booking.com and as I have used them quite alot I get a 15-20% discount.

Generally you can't go wrong with hotels that have high review scores, just read the reviews and you get an idea if a hotel is lacking in any areas.
But always cross reference the prices between Agoda, booking.com, hotels.com etc etc as some do offer much better prices than the others.
I Generally find chain hotels to be far more expensive compared to others for similar room types and sizes.