No one is slamming a whole line. I've used quite a few Cisco/Linksys routers, waps and switches for a long time. Most recently I really liked my RSV4000. My success with Cisco/Linksys over the years was a large part of the reason why I bought the E4200V2.
But I was really disappointed with this one. For one thing, I do know how to set up a router and network. That's not the problem here. And my comments aren't based on reviews. They are based on actually having in my hands and trying the three routers I identified that had been discussed in this thread. The Buffalo I had used for over a year. It had good range and throughput, but its connectivity was inconsistent. Devices would simply lose their connection for no good reason. So I ordered both the E4200V2 and the WNDR4000. The interface on the Cisco was not great, and while I could create a wired and wireless LAN, I could not get it to connect to my Verizon modem (set in bridge mode). Yes, I cloned the MAC address, and I reset it multiple times, and everything else. It just didn't work. After wasting about 3 hours of my time (including 30 totally useless minutes with Cisco tech support) I boxed it up to send back to Cisco. The Netgear WNDR4000 on the other hand, took about 15 minutes to configure, it was really easy to set up, it connected to every diverse device in the house right away (pcs, laptops, tablets, phones, IP camera, clock radio, TV, BD player, etc.) and it has not lost a single connection in six weeks. It has good range, good throughput, was a tremendous bargain, and was, from my own personal experience, by FAR the best product of the Cisco, Buffalo and Netgear wireless routers that I tried this time around.
I had originally intended to use the E4200V2 and had bought the Netgear because it was a bargain just to use as a spare or perhaps to add as a second WAP in a separate part of the house. Instead, I sent the E4200V2 back to Cisco and ordered second WNDR4000. But the range and throughput is good enough on the Netgear I have had no need to set up a second WAP.
Thus, when the OP asked for a recommendation on a wireless router with guest access, I recommended the Netgear WNDR4000, and I would not recommend the Linksys E4200V2.
Is that enough "elaboration" for you? Just because you don't like the answer, you don't have to be so dismissive with all the "obviously you don't know what you're doing" nonsense.