The Houdini is noticeably more breathable than the Litespeed when using the mouth-test. I also like that the fabric texture is similar to those napkins that they drape over you at the dentist office - you know how it has tiny bumps or ridges? It seems like it won't smother your skin like the shiny inside of the Litespeed. That may just be appearances but I like it.
Functionally, the Houdini's hood is better than the Litespeed. The ingenious way of routing the shock cord like a headband in the hood allows the hood to cinch down around your head like a balaclava. The Litespeed hood still cinches well, but it's the traditional "face hole" with the loose hood still free to flap or shift around in the back. If the Houdini's tiny chest pocket were larger and used a vertical slit like the Litespeed, then the shirt would be perfect in my mind.
I got the Bali Blue color Houdini during the last Shoebuy.com deal. The color is really nice! With the 20% promo they were running, plus the 10% member discount, I paid $68.72 shipped.
Oh, thank you above poster for the MT101 hint! I just ordered a pair for $54.32 - seems cheap enough to try out!