I VTC as "please clarify your specific problem or add additional details". If you can't nail down your "software
development" requirements, I don't think it's possible to say in advance whether you could find the extra RAM overheads acceptable. I suspect the RAM is a major factor in this question. It's technically possible that it could be acceptable.
I think it could require a significant time investment either way, to find out whether it works well enough for you to accept. If you've got the time to test that, you can find out :-). If checking all the minimum system requirements, testing the actual performance, and working out a fallback plan sounds like maybe not a fun use of time, I think you should take that as a hint :-).
As quicker alternatives, you might consider using more sandboxed apps - Flatpack or Snapper, and/or normal virtual machines in some cases, and/or "fast user switching" with a second account which does not have sudo access.
Also try to use Wayland with native Wayland applications. Apps running under X are not properly protected from each other, even if they are otherwise sandboxed (I assume even if using X as emulated by XWayland?). I don't know how far Ubuntu have come in solving the X problem yet.
Fedora 28 includes a
firefox-wayland package. RedHat developers also seem to be providing an experimental Flatpak of Firefox here.
"Suspend/resume bugs are quite frustrating; [Ryabitsev] can only resume correctly 10% of the time [on Qubes], so he doesn't bother." -- https://lwn.net/Articles/764048/ "Life behind the tinfoil curtain":
(It uses Xen for some reason? which is fairly different to other Linux virtualization. That's the first thing I'd blame for suspend/resume... or other power management issues...).
"Qubes OS does require lots of RAM. He typically runs around ten VMs using 1-4GB each; the official requirements are for at least 4GB, "but you will not be a happy camper" with that amount of RAM. He recommends at least 16GB of RAM and fast, large SSD disks, preferably NVMe. Each application will be read cold from the disk, since the VMs will not share any of the OS caching—fast disks are a must."
RAM usage is going to kill you, either if you want to use VMs in the normal sense, or for some types of software development. If you want to develop various software, you might well end up wanting to be able to use VMs in the normal sense.
E.g. (when you don't use Qubes) I don't recommend trying to run more than two normal style VMs in 8GB. I guess I'm currently using a spinning HDD, and having an SSD can make a few more cases tolerable.
The Xen stuff is going to make VMs more obscure to work with / learn / troubleshoot as well.