I would do the Denon out of the brands/models you listed. It's the better product out of the 3 and probably the best Pre-amp on the market (at the least it shares company with very few others).
On another note:
Where are you seeing
THIS at? That's below dealer cost!

Heck, if I can find them for that I'll go to that source rather than Denon directly.
However, * cue the Storm Trooper march * April 1st, Denon is requiring ALL dealers to sign a dealer agreement stating that they are NOT allowed to post pricing below Denon's MAP. This is going to be a legally binding agreement and Denon will either sue (prob if the offender/offense is large enough) or (more than likely) cutoff the seller and potentially the distributor who sold to them. I have been told that they are 100% committed to this and that it's a very serious change for them.
This has silently been happening all over the industry for a few years. Online chop shops cause manufacturers soooooo many problems it's impossible for them to service the end user properly. This is for a variety of reasons, many of which have nothing to do with the price an end user pays.
- Epson has recently cut off a guy who was undercutting their projectors online and violating their dealer agreement. They not only refuse to sell him direct, but they have alerted every distributor they sell to his buying habits (even the big box shops). If someone is caught selling to him Epson will pull the line regardless of the account. And this guy aparently did over $1,000,000 in Epson products (not including accessories that he sold to go with them) last year and had a ton more orders coming in. His business is virtually destroyed now. Epson values their integrity and I think that Denon is going to be taking a similar stance.
A great many other companies do this and work hard to police their brands. Some even implement secret measures of ways to track their products so that they can find the original reseller who basically acts as a "fence". My advice to you, if you decide to go with it, would be to buy the Denon for $1100 before April 1st.