Using a different distro feels awkward. I am so used to how stuff is organized in Gentoo :) but it's still Linux, so no, it's only minor differences.

(Spcially, i hate when using a SystemD based distro, because i am not used to it and it honestly feels cumbersome compared to OpenRC. Gentoo also has SystemD support, it fully support it, but i never found the need for it, so i never switched, and never got familiar with it. My fault)

Last weekend i setup a laptop from deleting the windows partition to full LXQT desktop in 4 hours. The laptop is quite fast, and i skipped all ocmpiler hogs like firefox (choosed firefox-bin) and rust (choosed rust-bin). Later on, i also installed a full plasma+kde environment in some more 10 hours (all compile time in background, while using the laptop on LXQT).

The biggest downside of Gentoo is being so niche, i always fear that some day it will be abandoned due to too few people maintaining it. I had this fear for the last 10 years, and never happened, so.

There are no real downsides to Gentoo IMHO, except becoming too expert with Linux :)