First: The credit scores a individual can pull are not the same scores that a mortgage professional receives when requesting a three bureau merge for the purpose of a mortgage application. So, it would be impossible to know if your score will remain the same. Second, mortgage lenders use the middle score of three scores....therefore, knowing you have a 700 score would not guarantee anything specific for rates/pricing. Your other two scores may be higher!
There are any number of facts that will affect your pricing on a mortgage loan, including (but not limited to): Credit score, reserves, type of property, location of the property...and the list goes on.
I am not sure I think it is "still a lender's market"; however, I see very few transactions that are the "slam dunk" that the consumer was thinking from the outside looking in. A few years back, fogging a mirror would get you a mortgage. Today it takes documentation, perserverence and the assistance of a highly educated and experienced mortgage professional.
I have talked with a lot of consumers who lost a great opportunity because they were more focused on the "cheapest" deal instead of focusing on the entire process. I don't promise any consumer I will have the lowest rate in town...I do promise I can close the transaction if we start it. And, I think you will find that is the case with most mortgage professionals.
Lastly, for the record, 700 is a pretty good credit score. Though some lenders/products/programs require higher...,not just for the best rate, but to qualify at all. Most programs/products will do down to 640 scores and a few to 620. Hope this info helps you! Best of luck!
Short answer is that, with a small variance for the loan type, you should be able to get very close to the best rates available with a 700 credit score. There are some instances where combined factors could make your rate noticeably worse than if you had, say, a 780, but again, without going into too much detail, your 700 should still keep you in good rate standing.
If you have questions or if I can help, please let me know.