Well … It depends how you look at it. H2+ is x86 and consumes more electricity. And RAM must be purchased separately.
It’s all a matter of what goal you want to achieve. Stronger one unit based on x86, or two weaker ones based on ARM.
Personally, I have not noticed any problems with the power. For HC2 and 3.5 HDD, the power supply is important. If there are power outages, it is rather on the entire unit. A decent and efficient PSU, otherwise there will be problems.
I have not noticed any problems with the sata-usb3 bridge. And I pushed a whole lot of TB through.
Personally, I do not use GlusterFS now, I usually have two units, master and slave, at my clients. Slave does 1:1 backup if master fails, no data loss. If there are technical conditions such as additional physical location and broad link, the master and slave have additional physical separation.
The advantage of two HCs over one H2 is physical separation. But this obviously does not have to be an advantage for everyone.
With two units, you can also separate services or make them HA. like your own dns1, dns2.
Contrary to many opinions and preferences, RAID is not a backup. For soho, two units as mirrored copies may be a better solution than one unit and some RAID1. But it also depends on the specific application of the given user.
I have one user who owns 5 HC2 units in different locations and they all work as 1:1 copy. Such was his request 
Resistant to anything, fire, water, theft, earthquake … of course hdd encrypted without key locally. In addition, the HC is compact in size, in the event of an emergency at home, like a fire, you can literally grab it in one hand and run away with the data. Or take it on vacation as a mobile NAS with your favorite movies / music. 
Just think of it as an experiment, and a platform for getting familiar with ARM as a break from x86.
In the worst case, you can always sell or give someone a gift.