There are a few products on the market that appear to be very similar to the LAN iSilencer, and I am sure each one has its reason for its pricing.
It could come down to simply better/more expensive components. I have not found a lot of internal shots of these others (there are some of ours on the website) so I couldn't speak to them.
It may simply come down to iFi breaking down a price barrier in this category, but the best I can say is at our price I would at least give it a try first to see if it offers you any benefit before moving to the higher-end stuff. I say that because I once tried a very inexpensive DDC to see if it made a difference for me, (it did) and the next step up, (hundreds of dollars) also made a finer improvement, but I would not have made the second step if the first wasn't productive.
With anything in this category, sometimes you just gotta test drive it if possible!
Hope that helps,
Cheers!!