The stylus will work with any tablet that has a capacitive touch screen. Check you tablet's specs, if it has a capacitive screen (and I suspect it does) then the stylus will work fine. Once you have that figured out it comes down to preference, this stylus uses a rubber tip, some others use a fabric tip, The material affects the amount of drag on the screen and it working for your purposes or not all comes down to how it feels to you.
For general use this stylus is great, if you were trying to do something specialized like use an art app you might like the fabric tip better. If you want to look at or try a fabric tip stylus, boxwave is a good brand, I bought one along with the amazon basics one and use them both for different purposes, neither is outright better than the other. Again it all comes down to preference.
Truthfully I don't know. I've never seen an Asus Transformer 300 Tablet. But if it has a virtual keyboard on the screen it should work. This Stylus doesn't plug into the unit you are using. That little lanyard you see in the pic is just something to hang onto or use for who knows what. It is not a micro or mini usb connector. I took mine off. It's just in the way anyway. Chances are it will work just fine with your unit.