I currently practice on a 50mm Chrome x-pole (circa 2008). I'm 5'11, 125 lbs. The diameter and overall experience has been pretty good.  BUT I got on some 45mm's recently and realized a big differnece in perfomance (I could do more, much easier, etc)

So I'm getting a second pole and trying to decide between chrome or titanium gold 45mm... I'd love to hear about the 40mm (and the 38! WTF!) if anyone has experience. Just trying to hear what works best for others. Thanks!

I have all of these finishes and sizes...From my experience, here is what you should consider. 

If your a seasoned dancer (sounds like you are) and you're looking for better grip go with TG or Brass. Chrome is best for new dancers and those who love to do static spins. 

BRASS: Do you sweat a lot when you dance or live in a warm climate, is your poel space warm? If yes,  then go with the Brass finish. When I lived in the Midwest I couldn't grip the brass, here in Vegas it's been wonderful!!! Sweaty hands work better with the brass, then TG or chrome.

TITANIUM: Do you have troubles staying warm, or live in a cool/cold climate, is your pole space cool? Then go with Titanium, This finish has worked well for me in ALL climates! 

I love my 40mm but I still love my 45mm poles too! I'm 5'8" ....The 40 is wonderful for creating new lines and extensions, but I prefer split grip work on the 45. There are benefits to all of the different diameter poles. I've tried 38's too and they don't feel much different than the 40. 

Thank you so much!!! What you said confirms what I was intuitively thinking to do, which is go with TG 45mm... but those nicer lines you mention sound intriguing... I am focusing in on split grip work big time lately (and I have hardly any use for static spins, lol) and with already bigger hands than many, I guess TG 45 is truly my best bet all around.  And it is cold in Chicago so the finish sounds good... Do you know what it is technically, that makes the TG better than chrome for grip?

I don't know technically, as in chemistry wise. [www.studioveena.com] like the 45 tg is a good fit for you!!

For me, I love the 38 the most, then the 45 (I haven't used a 40, but it should be similar to a 38, I think.) I can do all the moves that I know on a 45, on the 38, but I can do moves on a 38 that I cannot do on a 45. I have seriously short stubby limbs, hands, and a short torso, so the skinny pole is my best friend. I like brass for hand grip, though it grabs my skin too much when I am really warm. Chrome and TG can be too grippy for me as well, so I guess I'm just sticky. Stainless is the only material that doesn't give my skin the death grip. I do slide a lot in certain places on my bady (like upper back and tushy) on TG and chrome, while I don't slide so much on brass and PC.