What you've got to think though mate is using SRP only fills the swirl marks in. In a month or two time you'll need to do it again as it would of washed out and the exact same swirls would be visible again. If you tried using a cutting compound such as Menzerna FG400 (which I'm currently using on my machine polisher) it would take you hours and hours just to do a tiny little bit, especially with German paint as it's really tough. Whereas SRP fills the swirl marks, a cutting compound removes a very fine layer of the top coat thus getting rid of the swirl marks all together. The only way they would reappear is if the car isn't washed correctly and more swirl marks are caused.
As you can see using SRP does get you some amazing results by hand and I actually used it before I started machine polishing. I'd highly recommend getting a DA and giving it a go. Once you've done it once you shouldn't really need to do it again as long as you give it a safe wash everytime and be careful of contaminates.
As Rich said photos don't mean too much but I thought I'd post these anyway. All in all it's taken me 5 hours to do that side of the car and the bootlid. This is doing 4 passes with the cutting compound, 3 passes with a finishing polish and 1 layer of Collinite.
If you want to know anything else feel free to ask :). I'm no means a expert but I've learnt quite a few things since starting :)