Each brand has many models… so not sure a simple guide is possible! As for me, over the last 7 or 8 years, I have moved from a Lemke to a Schleese Obrigado, to a Custom Wolfgang, and now back to a Schleese but now the Pro model.
To the OP: I was very impressed by the methodology of the Schleese saddle fitters - their method is partially documented in videos on their website. They asked what I struggled with as a rider. THey measured me (various measurements), they took multiple measurements of my horse, including weight bearing area, shoulder development, shape of back and barrel… then recommended knee roll, panel length, etc. So far so good.
That all said, when I got my Wolfgang, the agent/fitter watched me ride, looked at the horse,a nd put exactly the right saddle on his back… I knew it was the right one within 30 seconds.
WHy do I have a different saddle now? My horse has developed. I have changed as a rider. And I needed a saddle with the stirrup bars farther back.
SO the sort answer is - the best saddle is the one that fits your horse and you, where you are in you riding and where your horse is in his training, today.