I have two contractors coming to give me bids next week to give me bids. One contractor is selling a water furnace system,while the other is talking about a DX earthlinked system.
 Is one system better than the other,and is there going to be a big price difference, all things being about the same.

The possibility leans towards that the DX system will be a lower price. However, it varies immensely from contractor to contractor.

Just make sure they size, design, and install it correctly.

All systems have their limits, you are not comparing apples to apples if these are the only to quotes you get.
Check with manufacturer's web-sites for other refferals if need be. I'm running across a disturbing trend recently (as geo is growing so rapidly) of contractor's who are not doing load calculations and throwing around very unrealistic numbers. A house I am working on now in MI recieved 1 estimate from a "contractor" who suggested all the heating and cooling could be done for $440/year (this is a 3 story home over a walkout basement. Another contractor and I were within 10% of each other ($1,100ish).
Do your home work; check refrences and you'll be fine with DX or water source.
Joe

Huh, that number sounds familiar :).

Of course part of it was from an estimated 4.3 cents / KWH but still I'd like to know who he knows to get that kind of rate.