I have had many airport products. I think will avoid timecapsule versions going forward because disk seen to last just a couple of years.
Before this spring, I had to use 3 additional aiports (1 extreme for bridge/extend and 2 expresses to extend) to go with the main airport extreme to cover my house, which isn't that big.
My network started to get flakey and I thought it might be load. With tvs, bluerays, xboxes, ios devices, remote controls, ..... all using network, I thought maybe last generation airport timecapsule was reaching limits. Note, a simple thing like my son enabling his nitendo ds (which uses WEP and airport doesn't handle) could cause things to really break down.
In the spring, I tried the netgear and asus ac routers. I decided on asus because poor parental controls on netgear.
I have been able to drop the use of the airport expresses and get fine coverage in my house. I still have an extra router (asus ac) because I need a bridge in the bedroom for non-wireless directv.
This is all without any ac devices so the lastest generation of routers work much better for me.
I really do like the integrate of the airport with my mac mini server so I may give these a try.