I have both, and lean toward the phoenix, but I still a think gardiner poles are better made. Although maintained well, I.e cleaned thoroughly once a month, the phoenix will last a good 2 years and more,
There's not much in it, I really like both, but I don't own a shorter gardiner slx pole, so can't comment, but I do have the slx35 and a clx18. I don't think you'll be dissaponted with either, i wild say the facelift brush is much better than gardiner super lite though, it's a fantastic brush, amazing splay, and scrubbing power, a real joy to use, and lasts for ages.
Alex will be bringing out new brushes next year though, so who knows, maybe he'll trump the lot again!
I like the narrower width of the phoenix, and love the clamps. the phoenix also has a 'shiny' texture to it, and glides very nicely. I still highly rate gardiner poles and if could buy an slx18 cash price I would, but I'm able to get phoenix poles a lot cheaper, and really enjoy using them, I have the phoenix 18 and 25 carbon x's