Note also that RoomFit has a very strange and non-standard horizontal axis - it seems to have linear scale 20-50Hz, log scale above 100Hz, and somekind of transition region between 50Hz to 100Hz. Additionally, it doesn't preserve the vertical scale constant - I've seen examples where RoomFit vertical scale was only 10dB, and examples where it was >50dB.
All this unfortunately makes the RoomFit responses quite difficult to compare visually with those measured with any other tools.
Actually higher Q value means a sharper filter (affecting less frequencies) and a lower Q value means a wider filter (affecting a larger set of adjoining frequencies. Here's an example to illustrate:
In my experience the choice of Q-value that RoomFit uses will depend on several factors, including the min/max gain, max Q and frequency range.
I still mostly create my corrections in REW and then load them manually in a RoomFit profile - meaning I change all RoomFit PEQ values accordingly.
But with every release there's less and less difference between what I create in REW and what RoomFit can generate automatically - which is truly great to see!