Wireless N adapter: PCI or usb?

So I have an asus pce-n15 pci express n adapter already but it is horrible and I keep having my signal drop and disconnect randomly all the time. So I am looking to replace it but I am wondering if I should get another brand pci one or a usb adapter? What are the advantages and drawbacks of each one? Reliability would be very important for me as my current adapter is not reliable at all

No my pc is in my room about two rooms away from my router which is an att uverse router. At first I thought it was because of where my room was that was causing my computer to randomly have no internet connection works fine in my room and never disconnects. Oo and when this happens on my pc it doesnt disconnect from the network, its always connected to the network but when my internet stop working it just says I cant connect to the internet

Yeah it only happens on my pc because when I don't have connection my router is still good and I can still access the internet on my laptop so I know it's something wrong with my wireless adapter