Regarding chargers and related equipment...
One thing to keep in mind when selecting chargers, especially when charging large cells packs, is making sure the watt rating of the chargers will allow for a decent charge. That charger that will charge up to four lipos at once is a nice charger, especially if youre only going to be charging 2s. But I think its only rated at 50 watts per port so your 4s batts will only be able to charge just under 3.5 amps. Consequently, it may take a 5000 mah battery about 1.5 hours to charge. Not to mention it is pushing the limits of the charger, and in my experience makes chargers have shorter life and definitely produce alot of heat.
Secondly, finding a good power supply that is appropriate to provide power to your chargers is very important. I dont want to get into the math but it is very simple. Just make sure you are conservative and account for any inefficiencies that will exist in the chargers. That way your power supplies can have plently of wattage to power the chargers.
That maxamps power supply is nice, but is overpriced for what you get. That supply is just a file server 12v, 47 amp supply. I can almost gurantee its not a new unit, as they are very expensive new. One can find a good supply on ebay that is the same one as the maxpamps for around 20 dollars. Or you can buy a supply from a guy named feather merchant rc (just google his name) and you can obtain two of those supplies for the cost of one of the maxamps. This is the route I took....Ill show pics at the bottom. File servers are great supplies though. They provide a clean, very well regulated dc source, that is designed to run 24/7.
Bottom line, think about what will work for you and what you will be charging most of the time. Then go from there.
Heres my setup.
I have 3 - iCharger 208b's ran off 24 volts. These chargers can do 20 amps but I will never charge at that rate. Usually I charge at 10 amps for all my batteries (I use 2s, 3s, and 5s). I wired 2 - 12 volt supplies in series for 24 volts at 47 amps. Mounted them in a case under some lexan. Then I added a couple of flush mount banana jacks for 12 volt and 24 volt availability and a few fans to circulate air. I love this setup because at the track I dont have to fiddle with setting up chargers or having my charging equipment loosely thrown in a tool box like I see so many do. I also put in a flush mount iec receptacle in the back of the case. Makes things nice, just plug in the case and its all ready to go, and my batteries and pigtails are stored nice and cleanly.