If you plan on getting a under quilt I would go with the side zip. I had a bottom entry Hennessy and found I was somewhat limited.
I also found that on really hot days the bottom entry would get hot inside, and all I wanted to do was open my bug net and let the breeze in. I also couldn't cook break fast in bed if I so choose.
But then again you could always get a 2qzq mod and have the best of both worlds.
One thing I did like, however, was the fact I could quickly escape the hordes of mosquitoes that Maine gets plagued with.
"In seed time learn, in harvest teach, in winter enjoy." -D'Signore's, Tide Mill Farm, Edmunds, Maine.