GOG reviews seem to be quite mixed. Whats the gameplay actually like? Are the mixed pro and cons in the reviews accurate?. Currently on sale.. tempted

Pathfinder Kingmaker is worth its price. Generally if you like isometric, Baldur's Gate like RPGs, you should be pleased. I always had some remarks regarding some elements of the game however. For me the main questline is not good enough. Also not everyone likes the quite slow pace of the game. Generally be prepared for 130 hours of gameplay, if you want to manage your kingdom (which also isn't a great element of the game in overall) and do side stuff. If you prefer turn-based combat (which is wonderful BTW!), it'll take a lot more time to finish the game. Both Pathfinder games favor those who like to play slowly and dedicate fully to playing them.

If you want to buy the game, I strongly advise installing it on a SSD. While loading time is fine early on, things will slow down to a crawl as you advance in later chapters.