Why?
I think some of the benefit of the LS swaps is the info avail for the do it yourself guys...
FABO has the MOST hemi swap info I have found. This is a freat place for info, with some really good guys providing it.
However, there are so many sites with LS swap info it is very easy to find what you need to know. There is so much more info about tuning, repinning a ecu/harness, and other details of the swap that would make it a easier or cheaper venture in my book. Like abodyjoe says the aftermarket support is huge too, look into it... I have... Yes, you can buy hemi swap parts or ecus from a few vendors, but there are literally dozens of companies selling LS swap stuff. We all know supply and demand rules, more vendors =cheaper prices and better product development/options.
The hemi swap is a good thing, I'm really happy I did it, and wouldn't change it at all. But the availability of LS parts, and knowledge online I think it is a great option for the true "poor mans Hotrod build". The "mopar or nothing" attitude is crazy, I say do it Abodyjoe...
Joe