I am sure you have done your work well, you don't buy a $855K home everyday....some one said to me "some times it is not how much you think your house is worth..it how much the sellers want to pay for it".
If you like it and have the money GO FOR IT!! Congratulations!

I would really question the asking price. Have your agent pull comparables for the area if any and present them with your offer. I recently sold a home that was assessed at $450k and we sold at $324k. You might very well be paying way more than it is worth. As for Greg's comment on the appraisal - you might not get a loan for the home in question.

Melissa Leetzow e-PRO Realtor
Coldwell Banker Primus

Do you homework with your agent and put in your best offer. Tell them to take it or leave it. Even if you did overpay, the property will not appraise and you will be protected. This does happen in today's market and many times the seller will reduce the contract price....really what are there options?? Good Luck!
Greg/REMAX