Ian, the "value" in a CPL is really only dependent on two things.
Firstly, the experience and quality of your instructor and second, the amount of work you're willing to put into it to get the most out of it.
Assuming you've got the second one covered as that's out of everyone else's hands, you need to make a decision about whether you can find an instructor who meets the grade. You need to ask what they're trying to achieve with their commercial training as there needs to be an overall philosophy in place prior to commencing your training. While you can pass the test by simply meeting all the applicable criteria on the CPL Test form, the actual benefit you get out of the training and licence are dependent on a lot more than simply ticking the boxes on the form.
In my opinion, if you're going to spend an extra "x" thousand dollars on a CPL - depending on your current experience levels - you'd be better putting that money into a Command Instrument Rating. While you need to consider how much money you can than spend on keeping yourself current, and I don't mean just the bare CAO 40.2.1 minimums, the experience you get from that will be far more beneficial to your overall competency levels and decision making abilities than a CPL will.