As everyone else has said, it comes in a nice transparent black bottle so you can always see how much is left. The bottle is nice and easy to squeeze product out of.
I haven't noticed a discernible smell to this product which I think is good as you wouldn't really want your brushes smelling of anything.
I will get a lot of washes out of this bottle, although it is small, you do not need to squeeze a handful of product out to get all your brushes clean. I usually get about 10 brushes clean using about 2 or 3 20 cent piece sized squeezes.
The reason I've given this such an average rating is that it is very good at getting all your powder brushes clean, it's not so good on cleaning the brushes that have had liquid makeup on them - I.E double wear foundation. I have to do my foundation brush 3 times and I'm still not 100% happy with the cleanliness of it. The other this I don't like is the price - I got this off a NZ website for something like $12 and feel it's pretty overpriced. Wouldn't pay this much for it again. I think I'll look at cheaper alternatives.
I purchased my e.l.f brush shampoo from Kmart for about $10 a few months ago. I was excited to try this product as I have only ever cleaned my brushes with detergent or hand wash (bad idea I know). This resulted in me having to purchase new brushes regularly so I hoped this product would make them last a little longer.
The shampoo didn't really foam up as I thought it would, I found I had to use a lot of product to cover all my brushes. It also did not fully clean my brushes or lift any of the foundation stains. It did however clean off all the makeup dirt and left them smelling fresh and clean. I don't think I will use this product to deep clean my brushes but could be good for light cleaning in between washes.