I've never used the Sampsons. I used a Thunderheader on my '03 Low Rider, Nice pipe but too loud for me. Also the heat shields do not come with the pipe, you have to order them seperately and pay extra for them. It was an expensive setup. I used a V&H ProPipe on my '03 Heritage. It was a great pipe with a great sound, not too loud unless you really opened her up. I was very satisfied with the V&H ProPipe. I am currently installing one on my '07 Heritage.
I have the D&D Fatcats on my 07 Heritage. Great quality and a very easy install. Getting the old pipes off was more difficult. Nice low rumble and a great help with the heat issues of the 07's.