This question gets well aired on the forum every few months
It all depends what your criteria are.
Plenty of beginners and improvers get a lot out of Trout Fisherman and Today's Fly Fisher (or is it Total Fly Fishing now ?), but the consensus is that you more or less outgrow either or both as your experience and skill develop.
A lot of us older lags like FF & FT while commenting that its production values - not the content - might be better. Some like Trout & Salmon, others bemoan that mag's relative lack of editorial content as compared to adverts and the (now superfluous ?) fishing reports. Yer pays yer money....
A few of us have fond memories of the old "Angling" magazine that Brian Harris formerly edited - however the lack of an obvious successor to it probably shows that the modern appetite is for targeted and specialist offerings as opposed to a mag that seeks to cover all 3 disciplines of coarse, game and sea.