I had Staintunes on my '03. I thought they were pretty good. Looked great on the bike, ovals are cool, but the welds weren't all clean. Being one piece they went on easy but the sizing on the pipes was small and it messed up the existing newish gaskets. They didn't come with spare gaskets so I had to order 2 new ones and tap out the inside of the pipe a bit. The spun SS packing is interesting. It has longevity for sure. When packed in a metal can the sound is full and rich, yes, and real raspy. Distinctive, very wicked. Maybe not for everyone. That's where the plugs come in as you can tone it down. I thought the plugs were cool at the time, but don't now. Down side of a metal can packed with spun steel is that they were very buzzy at speed. Didn't like that. They used to offer carbon fiber cans, maybe they still do. If I went with Staintunes again it would only be in carbon fiber. Current price is $770 and they are made in Oz. Much cheaper at the time, there was enough margin on CTB's price to my dealer that he could give me a nice discount.
I have Holeshots on my '04 and I love 'em. They look great and sound fantastic. Overall construction is top notch but they will never look quite as clean as Staintunes (or stock) because they are riveted together and use hanger straps. That said they have traditional fiberglass packing which, if you did the miles, could easily be replaced if burned out. They are also 2 piece units which require some time to install but everything was consistent and properly sized. No bunged up gaskets as they slid on perfectly over my barely worn stock ones. No big deal if you mashed them or they're worn out because they come with 2 new ones. Dale Walker sez replace upon install but mine looked new and now I have spares. He also specifies a copper gasket seal to be applied at the can joint and I had to go out for it. Staintunes at the time did not come with locknuts for the hanger bolts and I had one back out on me. Probably my fault. Holeshots come with locknuts. (Side note; the captive hanger bolt set up on the stock cans is very trick and can't be beat). On test ride they were buzzy too but soon mellowed out with no buzz. They cost $620, are made in the USA.
Dale Walker is the only American working on a full system and the only one in the world that will use 2 cans (this influenced me greatly as well this time around). He is the nicest guy with a wealth of knowledge who'll answer your phone call and think nothing of spending some time talking with you about the science of performance tuning. He told me that he's now testing the full system for the last time, this time with a crossover pipe in the header to see if he can improve upon what he's got so far. Also he's doing the testing with a Dobeck TFI and the stock map instead of a PCIII as he feels it works, it's cheaper and easier. I think Dobeck started/was with Dynojet.