Zoeva they are amazing, their products are the perfect dupes for MAC brushes. They are amazing quality and even clean well, they don't scratch your eyelid and look so expensive. I have the flat top brush which is perfect for applying colour onto your lid or loose pigments and a petite crease brush which is ideal for fine detail or simply for a small crease.
The other three brushes are off Ebay something I was extremely cautious about doing. I couldn't understand how a cheap brush could be good quality but believe me it's true. I bought an eye set from a company in Hong Kong which meant it was cheaper but took a least a month to arrive. The set contains every eye brush you may need but my favourite is a fluffy blending brush which will blend anything. Also an angled brush and a lower lash line brush are contained within my stash which come in handy as well. I have had these brushes since Christmas and I have not yet witnessed any fall out so it a win for the cheap brushes. I don't think you need to have thousands of brushes that you don't need but a few which are more use than loads of brushes that you don't use.
What are your must have brushes?