The comfort of these vary so much by condo/hotel.
We often book condos and don't have enough beds for everyone unless hydabeds are utilized or situations where there are enough beds, but we don't want opposite sex teens sleeping together. So basically we are within the occupancy limits, but we don't have the bedding configuration we want. Happens to us alot as we book large condos frequently that we stay in with extended family groups. Unless we know for sure that the sofa sleeper are comfortable based on reviews, insight from employees at the properties, or previous experience, we bring along one of those inflatable beds, which are very comfortable per DS 16. We bought a single bed like this for about $65 that fits in a duffle bag. You just plug it in, turn a knob and it automaticlly inflates. You turn another knob and it automatically deflates. Since we fly Southwest alot ,and you get two free bags per person, it's no big deal at all to bring this along. We usually also bring a twin fitted top sheet and just use their bedding from the hydabed -- pillows and blankets.
We don't know about the place you are staying:
Examples of our recent experiences though:
Sofa sleeper bed at the Flamingo Hilton in Las Vegas was super comfortable // left blow up in duffle bag
Sofa sleeper at Myan Palace in Puerto Vallara, Mexico was super comfortable // left blow up in duffle bag
Soft sleeper at Sea Captain Inn, Clearwater was not comfortable and we used the blowup
Soft sleeper at Big Cedar Lodge in Branson, MO was not comfortable and we used the blowup.
Sometimes too, depending on the size of our party, we want to keep the common area available and use a blow up even when there is a comfortable sleeper sofa.