Steve Kitch Mastering doesn't post before and after samples for a number of reasons and you’ll find most proper mastering studios/engineers don't either. A lot of $5 a track 'bedroom mastering companies' tend to do this - artificially enhancing the difference to make you think that they are amazing. It's not always appropriate to make a dramatic change when mastering so posting examples where there is a huge contrast can lead to false expectations. Louder = better isn’t necessarily true. The brain is easily fooled.
In terms of taste and context then the mastering should appropriate for the track and client requirements. If an example was posted that happened to be ‘warm and dynamic’ but you liked ‘clean and pumping’ then that would influence your decision. Both is possible depending on what you need.
The solution is to provide new clients with a test master so you can hear the effects of the mastering on your own material. Its the only way you’ll get a grasp on everything involved and get a proper judgment. You can listen to examples of other music or read up on tons of websites, but the best thing is to hear the results on your own music.
Don't forget you can always listen to music mastered at Steve Kitch Mastering via Spotify, Apple Music and other streaming services.