Learn on the R22 and you still need to convert.
Manual and automatic car comparison is not really appropriate in this case (1.8 ford focus v's a 1.2 corsa is more appropriate). The R44 is more stable but it has more issues with speed, power and control, 4 seats, loading etc etc...
If £££ arent an issue then learn in what you want to learn in. Yes the R22 is cheaper and yes it does a good job. The military doesnt teach in Bell47s anymore yet the Bell 47 teaches people a lot that the AS350HT2 and R22 doesnt.
The R22 is more cost effective
The R22 was not designed for the training market (Frank Robinson freely admits this)
The R22 did get me to where I am today - I could not afford the R44
I no longer fly the R22