PP and Betfair have good slot promotions with sensible wagering requirements. Free games for big sports events too.That said they stopped promotions for Betfair Arcade and PP Games once I had won a bit and only give me Casino promotions.
They don’t have the range of games, but some can hit big if you try a few with not many spins. Three Musketeers gave me £172 on the first offer with minimum stake, then a trip to the Exclusive Room for £70. Haven’t got anywhere near that since, 4 and 6 quid offers and lucky to get to the second room with the red bonus. The spin bonus never seems to go beyond 38x.
Never had any problems with payouts with them and the Exchange offers some great odds for backers.