More lights = more plants
The risk with the chinese ones is that something goes wrong and they need to go back... then you are really fucked unless you got a backup while you wait. It's definitely the better deal though.
Have you thought about going with high output fluorescents? Not as expensive as LEDs and if done right can get good results. They weren't a very good option for me due to the limited growspace (high output t5s generally only come in 4' and 2' neither of which work well for me - found 3' ones but only with a certain fixture to run them i didn't want). Something to consider... 2' or 4' t5s might work well for your grow. Not as cool or energy efficient as LEDs but still far better than HID.
If you go with the blackstars don't buy at list price. Make them an offer. I know they will definitely go down to $265 on a single light purchase (what I got my veg light for)
I'm not sure one blackstar is going to produce great results for more than one medium sized plant or 2 small ones, so not sure it's going to get you where you want. The # of plants you have going now might barely fit in the usable light under the blackstar... they do provide side lighting but I'm not sure I'd trust flowering buds anywhere but pretty close to underneath the light. The two light option is probably the best for your situation other than the fact that it means shipping from china/all that involves.
I keep 2-3 plants under 4 blackstars and still have not fully convinced myself I'm gonna see the yields I want, though still hoping
If there were just 2 blackstars in that same space I'd be a lot more worried it is definitely a lot better lighting in there with more of them. When I was hooking them up and had just 2 going the light was real good underneath them, in the other half of the cab not so much
Then again you could always add more of them later maybe
I know you're not as concerned on yield as I am since you don't smoke as much, so one blackstar could be just fine for what you need it for.