Like HighlandPete, I haven't done F10 to F30 but I have done E60 to E90 (520d to 330d).
The 5 Series' sheer size was nice, especially the boot space, but I haven't found the E90 to be too small. Just would be nice if it's boot was a little bit bigger. The F30 addresses this.
The E90 feels so much more connected and agile and just fun over the E60 too which is what the F30 feels like over the F10 having driven both but the jump is perhaps as severe as it was from E60 to E90.
Another 520d would've been nice, but my E90 330d is even better!!! Very very glad I did!