I have an AC/DC quad charger, similar to the HiTec unit, but it does 4 x 80W instead of 4 x 50W.
I had this before I came to U/C, because I wanted to charge 2 or 3 R/C sailplanes and a transmitter, or 2 planes and a transmitter and a 12v lead acid car battery for my winch, all at the same time.
Still, it works OK for me, I have 4 TP packs (actually 2 each TP and Hyperion) 4S x 2700, and they only take 20 minutes or so to balance charge from the storage voltage.
Also, when I get back, charging back to storage only takes about 20-30mins, max, if that.
So, while this isn't a "serious" charge rig, it works well at home and abroad for my multi-purpose needs.
If I was to want to fly lots of flights per day, back to back, I think this charger and my winch battery would handle things, providing I bring 3-4 batteries with me, preferably charged.
If I get more seriously into competition and more than a 4S pack, this charger would be limited, but for 4S it works fine for me. Love that it's AC/DC when I drive to a 2 day sailplane contest, I just plug in my stuff after dinner at the hotel and I'm all charged up in short order.
Here is a link to the same brand, but higher power charger that I have. This one is more powerful, 4x100W!
http://www.amazon.com/Q6400AC-Four-Channel-100Watt-10Amps-400Watts/dp/B00NKO9NEWVr,
Chris