I purchased this a couple of months ago and I personally think it is ok, it's not amazing, but it's not terrible.
It comes packaged in a plastic, long, lip-gloss like tube with a doe-foot applicator, which is functional for a while but you can tell that it's not the best quality. It opens, shuts and is secure - your concealer won't leak out onto all of the other makeup in your bag which is always a plus. But as I have had it for a while (I wouldn't say a long time, but I haven't owned it for a day and used it once) I can tell you the packaging is really not great in the long run.
The lid has cracked slightly at the base, not all the way through but it's getting there. Also, there is a block of black colour where the lid meets the bottle and this has slowly rubbed off on my fingers as I have used this. And this is quite annoying as you have to wash or wipe your fingers because they will be black.
Now onto the actual product!
Before
After
As you can see, it does it's job and I quite like the product under my eyes, although I do use another slightly creamier concealer on top.
I like to use this under my eyes as it just opens up and brightens the area (I use shade fair 15), and I also like to use it by the corner of my nose to reduce the redness. But I don't like to use this on my spots as it clings to every hair on your face. Now I'm not saying I have a hairy face as I don't! But, it just accentuates the tiny invisible hairs so that they are visible. It also creates a coating over them that you can actually peel off - how? I don't know. It may have something to do with the fact that Maybelline call it their first 'gel' concealer, but to me it's more of a thicker liquid.
So overall I would recommend it to someone who wants to cover dark circles but if spots are your main focus I wouldn't recommend it unless your skin is baby smooth!
Maybelline FitMe Retails at £5.99