If you don't have much gold, go for CM (Elegant xbow is decent wep, later you can go for Repeaters/Big Shot).
If you are rich person go for Pavise (shield is additional cost and you still need crossbow to shot; so instead of 1 item you have to buy 2).
*I played as PC and CM and I must say:
Pavise higher Ironflesh and power strike makes a difference.
As CM, I reload crossbows a bit faster (compared Arbalest reloading as PC and CM) and it's noticeable (at least for me).
If you are rich person go for Pavise (shield is additional cost and you still need crossbow to shot; so instead of 1 item you have to buy 2).
*I played as PC and CM and I must say:
Pavise higher Ironflesh and power strike makes a difference.
As CM, I reload crossbows a bit faster (compared Arbalest reloading as PC and CM) and it's noticeable (at least for me).