I know I am late to this...but I can tell you I purchased the ea3500. Thought I was making a wise purchase. I loved the ease of set-up...and I liked the form-factor (meaning my wife is not upset about how it looks). I liked the versatility and the ability to set-up a guest network, and the parental controls. However, I have found our laptops seem to drop the wireless signal quite often. Since it is multiple devices, I am assuming the router is the issue, not the laptops.
I am now trying to stream videos wirelessly to my smart TV and not having success at all. I don't know for sure, but I suspect it's the router.
I will likely look to buy an ASUS as I have heard/read nothing but positive information about them.
The numbers you reference signify the transmission speeds they are capable on both bands (2.4 and 5 GHz). Obviously a bigger number is faster. I can't answer if it's "fast enough" or not for you...but I generally believe that you should purchase as much as you can afford because you never know what you will want tomorrow...and that might need that extra capacity.