I don't and never have used a sponge, so I won't talk about it as I don't feel like I can have a valid opinion on something I've never used. I will, however, talk about the benefits and disadvantages to using your fingers or a brush when applying liquid foundation and which I use. If you are relatively new to make-up, in the predicament of not knowing which to use or even just simply reading this for no real reason, I hope this will give you some guidance and helpful information.
It is easy to spread and blend because your fingers warm up the foundation.
Always cleanse your hands before applying make-up so that bacteria is not exposed to the skin as this will cause break-outs.
As your fingers have pores it will naturally soak up some of the make-up before and during application so the coverage is more sheer. Depending on your preferences this could be good or bad.
Fingers might pull and drag on more mature skin a bit more than a brush would.
BrushBrushes that aren't cleaned regularly can accumulate bacteria inside the bristles which can cause breakouts, block pores and is just really bad for your skin! Imagine all that dead skin and dirty foundation that has been gathering up on the brush... This is especially bad for sensitive or acne-prone skin.
A dirty brush also means you may be changing the colour that you are choosing to apply to your skin as there is residues of an other colour you previously used on it. This can result in an un-even and patchy appearance.
If you don't blend the foundation out will it can create a streaky appearance.
It is great for those of you that don't like to get your hands dirty.
It is good to blend out areas where too much foundation has been applied.
There are many different brushes available to you on the market for a variety of prices. Obviously these aren't all for applying foundation but many are. You can use different types and sizes of brushes for a more precise application. This makes applying your foundation so much more personalized to cater to your preferences and needs.
The better the brush the better the coverage and overall look of your make-up. For a really good brush, such as MAC which is a popular choice, it can work out quite pricey; You've already bought the foundation and now you have to fork out more money for a brush to apply it with.
Did you guess which I prefer? I love to apply foundation with my hands. I used to use a brush but I keep finding myself going back to using my hands. It's not that I don't like using a brush, it's just over the years of using the two I have found that my skin looks so much more natural and less cakey if you use my fingers. I also find that when I do use my fingers, as oppose to a brush, I tend to use a lot less product as I can feel how much I am using. However, when I was squirting the foundation onto a brush I'd estimate how much I thought I'd use and have the 'yeah that should be enough' mentality but end up realizing that I'd gotten a bit too excited and exaggerated so all that extra product would just end up wasted, lying on the brush and just soaking up bacteria. I'm also quite lazy and really can't be bothered to clean brushes every week which is a must if you use them, or carry make-up brushes out with me to top up my make-up.
But, there is nothing wrong with your choice or preference because ultimately, it comes down to personal preference which will come through experimentation between the make-up tools and years of practice and applying make-up. Both using your fingers and a make-up brush comes with its pro's and con's, so which ever method you chose you can now make a more informed decision for yourself.