For simple homebrew, 11.0 now has browserhax and menuhax again, along with probably one of the biggest lists of entry points to date (seriously devs are just pushing them out non-stop, and I actually like that).
I've also heard that the Sound application built into the system is also exploitable, but I'll believe it once I see an actual release.
If you want to downgrade (only really useful if you want CFW, which in turn allows CIA installation) then downgrade is possible but difficult on 11.0
You can either hardmod (not too hard if you have some soldering experience, or you can pay to send it to someone to do it for you)
Or you can use a $5 DSiWare game, with the only problem for most being that you need access to a 3ds that is already hacked, along with it's owner being willing to system transfer to you.