As a Turkish sailor who sailed gulets for many years as well as western sail boats...
Gulets are usually (90% of the time) coastal cruisers that are not designed for sailing at all. As a matter of fact, the origin of the type is for hauling goods between the mainland and islands in Aegean, thus it gets stable as the load increases (like any freighter today).
But, and this is a big but, if you manage to find that elusive 10%, those are the kind of boats that're truly a dream to sail with interior
and exterior spaces second to none (including cats).
However, those 10% cost quite a bit of money
, even more than Oysters. Think about older Jongert 30T's, which were build copying traditional gulets with application of modern naval calculations. As a matter of fact Hoek is building most of their boats in Turkey as well with bits and pieces of ideas taken from gulets.
Last but certainly not least, a traditional gulet is a wooden boat and like any other wooden boat, their expenses can simply be summarized as "nightmare" and they're not that compatible for shorthanded crews. For houseboat, go for the steel
Long story short, if you happen to find a good one, they're darlings to have, but just like any other boat and I wouldn't change them even for Swans, however those cost 4-5 times more than the market average.