This little rubber polish holder is great! The base is wide enough to make it almost impossible to tip over and allows you to tip the bottle if the polish is getting low so you don't have to tip the holder. I can easily paint my nails without worrying about making a mess. I have tried it with a few different brands and it is quite flexible meaning that most bottles will fit, including wide bases like Revlon. A few brands don't quite fit or won't go in at all (I'm looking at you Sally Hansen and Ciate!), but the majority will fit so it isn't too much of an issue.
My only complaint is the colour, it only seems to be available in pink, I would have preferred something different, but I am not going to complain for the price. There are lots of these on ebay but the ones I got came in a pack of two, perfect for when you don't want a simple one colour manicure.
My polish holder was from this seller and a pack of two was £1.24, with shipping taking just over a week. I can't recommend this enough if you don't have a sturdy worktop, it really has made things easier for me.