I first posted this in 2016. And did buy another Hubba. My third. I do love that tent.
Next time I will go for the MEC Spark, I think. It’s cheaper. And has far better waterproofing ratings.
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I’m a Hubba guy. Hundreds of nights in the iconic one man tent and I’ve no complaints.
Slightly lighter, slightly cheaper is the new MEC Spark.
besthike.com 
I have a 2 person Hubba and I’m not sure that I’m loving it just yet. It’s probably my own fault though. I find it’s been pretty cold. I loved my old Sierra Designs Vapor Light 2. But, I haven’t quite figured out how to get the vestibules tighter to the ground on the Hubba. The big open space on either side seems to let a lot of cold air in (and we usually do most of our hiking in the fall.) Any idea what I’m doing wrong?
I wouldn’t worry about the vestibule. You want air flow to reduce condensation.
Instead consider packing a better sleeping mattress or bag to stay warm.
I know exactly what you are referring to with the Hubba vestibule not coming down far enough. I had this issue on my first single Hubba and its a bit better on the new one. Furthermore the mesh walls come down much further to the floor (nylon only comes up few inches) so cold air directly on the body.
My new and improved Hubba has improved these issues. Much warmer with the nylon walls coming up a bit higher. So this one is much better for spring and fall. I use my older one for hot weather when i want more airflow.