I have been using phpbb forums for many years - usually I just pick some nice free style and use it.
However, during updates, I often end up having to select a new style due to incompatibilities etc.
I'm looking for hints where I should look for good quality styles, which are done by good designers, with high probability of continued future maintenance? I am willing to buy a style which is worth it and support the dev.
Web is full of shops offering various phpbb styles but hard to pick shops/styles which would be trustworthy according to the above-mentioned goals.
Would you please give me an advice on good and reliable styles, authors, shops?
(I know it's partly a subjective question but not too much I hope.)
buying a style is not going to assure you that you will not have to update it whenever you update phpbb.
some style designers might do that automatically and give you the updated version as part of your cost for the style.