GFPT,
Finishing your CPL in a SR20 has very good points and very bad points. Sunland is run by Steve Maltby, who is also the Cirrus sales rep for Australia, so they will have nothing but good things to say about the SR20. Getting independent opinion is a good idea.
If the SR20 has a glass cockpit it will get you used to using systems and give you an understanding of how they all work together; GPS, Autopilot, MFD and PFD all exchange information. The SR20 will also teach you the importance of keeping your speed on final. You can't cut the power and drift them in. The very high wing loading means you have to fly them all the way down to the flare; like the larger planes you will be flying as a CPL.
You say this will be to finish off your CPL? I presume then that you already have been flying a CSU aircraft and have the endorsement? The SR20 has a power lever rather than throttle and prop controls, so you won't get the experience of operating the power and pitch independently of each other. It is true that the SR20 is acceptable as a CPL trainer by CASA. but what about potential employers?
I suggest the SR20 is a good option, but if you don't have a CSU ticket you will need to get one on another aeroplane.
Walrus