I have to agree with @Mike Dittman ... i am not an appraiser... i have bought, renovated and sold a large number of houses over the last 8 years ... I know the Charlotte, NC market as well as any appraiser and in 100% of cases i always got appraisals when i purchased property for my own peace of mind. For goodness sake it is $300 ... If paying that $300 was the difference between me being wrong about a property or value it was worth it... in some cases when i have sold the property and person i was selling to was obtaining financing and their appraisal came in low i had my appraisal to submit as a rebuttal. If you are looking to get an idea of value a CMA is good. If you want what an appraiser is going to think when you go to sell the property getting a "subject to" appraisal upfront is ideal. *("Subject To" an appraisal of a property subject to you completing the described repairs, this is not an AS IS appraisal)
Lastly if the appraiser comes back and tells you the property is going to be worth less then you thought it would be after rehab that doesnt mean you cant still list it for that price... the appraisal is merely a guide post.
So there you go ... the democracy of the BP community. agree to disagree :)