I have had the BC168 and used it for many years but it did die after about 3-4 years.
I changed over to the CB86 which seems to just be a copy, been using this for close to 2 years now I would say.
As far as I know the BC168 isn't really made any more.
I have got the UNA9 but I haven't started using it but I really like the look and feel of it, looks really solid.
I think unless you have spotted a great deal (for example I grabbed the CB86 for $50 new on ebay) I would otherwise just get the UNA9 everytime.
If for any reason because you can split a large 18S battery pack in half and charge a battery pack that large in 1 go.. With S6 chargers its only 12S with one split or you could build a battery pack that you split into 3 sections for every charge but that really is just a bit too much stuffing around and 1 single plug/unplug-forget mistake and your battery pack/charger is going into meltdown.