A9LH sounds great and if I was going to buy a 3DS system I would probably install it.
Here's the thing: I already have a Gateway card with an 8 GB microSD card which is great for playing games in .3ds format. Just drag-and-drop the file and you're good to go. Furthermore, I also have access to the Homebrew launcher using Menuhax so I also have the option of using RxTools for installing games in .cia format or play Virtual Consol games, even GBA titles.
Is A9LH safer? Yes, but I'm not a newbie so believe me when I say that I will never "accidentally" update my 2DS.
Is A9LH faster? Yes. Coldbooting into Gateway through the HBL takes about 35 seconds, which is (I guess) 25 seconds slower? I think I'll survive...
Even though it is free, switching to A9LH would probably mean that I would have to buy a new SD card since my 4 GB card wouldn't be able to hold that many games.
I would be interested if it allowed me to boot into Gateway mode in an easy way, but from what I've read so far it seems to be quite a hassle.