I have bounced around between a 7 and an 8 for the last few years. I am just now trying to get back into playing seriously and just went back up to an 8.
I really like the APA rating system because it makes it much harder to beat a lower level player; particularly a 1 - 3. It really makes you concentrate and ensure that you play safeties if you don't have a shot. Against higher level players, it is generally whoever runs the table first with that one well timed safety that wins. And, of course, who is breaking better.
As an SL8 I do not want to play a 1, they have a huge advantage because they can luck in a few balls here and there and end up beating me.
Although I would prefer to play SL5's and above, I will play any Skill Level. I just have to play a little smarter against SL3's and below.
In 8 ball it is totally different. The handicap does not mean near as much as it does in 9 ball.
Just my thoughts.