Hi Emma,
I have used one before and highly recommend it. The cost of the service far out ways the benefits. I received a nice tidy report which allowed me to visualize and plan what to do with my property. The best thing was I was also given some idea's that I would have never thought of like converting my oversized pantry to a study nook. When my partner and I received the colour scheme we were unsure of the colour chosen only because we wouldnt have chosen it but once we finished painting we thought it looked amazing and people that saw the place previously are amazed.
I think you're completely correct that a consultant removes the emotion out of it and helps keep you focus one 1 thing and thats profit.
The company I used is called Hotspace check them out you wont regret it.