Advice on Zodiac/Polaris Robotic Pool Cleaners

[troygrr]

Hello,
For better or worse it appears as though Zodiac or Dolphin are the 2 primary robotic pool cleaners in NZ market, and so far I seem to be getting more people recommending the Zodiac range. What I can't understand however is how to choose one over another
The 2 I have been considering is either a VX50 or a CX35 - seen here http://www.zodiac.co.nz/robotic-cleaner. I have tried to get some help from dealers, however they just state the differences that I can see on the website (ie their high level config). I have even called and emailed Zodiac in NZ directly, and had no feedback to date - argh.

I have a concrete pool, 8x3m and am wanting one to clean floor, walls and waterline. From what I can see:
Both do floor, walls and waterline
Both have similar cleaning (ie >200 micron)
Both have an ebox and caddy
Both have adequate cable
Both use the same amount of power
VX50 is 4WD whereas CX35 is track driven - but what does this mean from my perspective?
VX50 has the lift function to make it easier to get it out - so that is useful (I guess)

So to my eye, there doesn't seem to be much difference, but there is a decent amount of difference in the price.

Can someone please offer some clarity around this?

Thanks in advance for any insight you can offer.
Cheers
Troy

[Teapot]

Yes save your money and vac manually, quicker easier and you won't miss bits. Sold my robot 5 years ago.