I'm historically a user of MapInfo Professional but have recently started using FME and have been talked into now testing out a copy of QGIS.
The main problem I've come across is that the coordinate systems used in QGIS do not appear to match what is produced by the other two?
For example, setting both MapInfo Professional and FME to BNG seems to generate a CRS of: +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=375,-111,431,0,0,0,0 +units=m +no_defs
This appears to differ form QGIS's interpretation of BNG which is; +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +towgs84=446.448,-125.157,542.06,0.15,0.247,0.842,-20.489 +units=m +no_defs
I'm going to admit that I have no idea what the towgs84 parameter relates to but the differences appear to cause a few meters of discrepancy when looking at features on the ground. Much as I like the simplicity of QGIS this could affect any decision to move forward with adopting the software in any capacity.
Could anybody provide me with a layman's explanation of what is going on?