I don't have a full RISC OS disc image to test with RPCemu, but a very quick
test running TwinWorld at the opening screen (ie playing the game but not
moving the player around, just watching things animate) gave:

RPCemu (SVN 124) with no sound: 13.5 MIPS
(I don't know if sound works or it's turned off)

VRPC 1.3 with sound: 44 MIPS

Both are with RISC OS Adjust, and counts taken from each app's cycle count.
Note that VRPC under WINE obscures its count most of the time in the mode
TwinWorld uses and it only flickers up occasionally, so I could be sampling
it at a time that isn't representative.

RPCemu is slicker - the mouse pointer works seamlessly from Linux to RISC
OS, while under VRPC there's the same split-pointers as under Windows (you
either have a RISC OS pointer which doesn't follow the Windows pointer well,
and have some points on the RO screen you can't reach because the RO pointer
stops moving once the Windows pointer has left the VRPC window.  Or there's
a capture-pointer mode where the Windows pointer disappears and you need to
press a key to get it back).  RPCemu supports left+right button=Menu click,
which doesn't work for me under either Windows or WINE (I have it set up as
the third button press on both Windows and X, but VRPC uses DirectInput and
so gets in below this configuration on Windows).

VRPC is better at ceding the processor when RISC OS isn't busy - RPCemu
makes my laptop hotter.  RPCemu just about has networking, but I haven't
played with it.  VRPC's networking is fine under WINE as far as I can see.

Something I should have mentioned in the original article is that you need
to be in the VRPC directory before running it, otherwise it can't find the
config file:
$ cd /windows/RISCOS/VirtualRiscPC-Adjust/
$ wine c:/RISCOS/VirtualRiscPC-Adjust/VirtualRPC-Adjust.exe

Theo