I think the choice will come doen to a few factors:
1. USB charging. Let's face it. USB charging is just plain convenient. You can charge pretty much anywhere, whether it be at home or the office with a wall wart, from a PC, in your car, on the go with a powerbank, or in the wilderness with a solar phone charger or Biolite stove. And if you lose a wall wart, chances are you have TONS more that you have collected from phones and various other gadgets over the years. With the VP2, you are limited to the supplied wall wart and car charger. This can also be somewhat of an issue for traveling, as you will need to pack a separate wall wart for your phone and your charger. With the Plus Master, you can just pack one wall wart. BUT, if none of this is important (and it isn't for many people out there), there is certainly nothing wrong with the VP2.
2. Different Li-Ion charge voltages. As has been said, with the Plus Master, you are limited to 4.2V ONLY. This means NO LiFePO4 charging. And it means that you cannot fully charge 4.35V batteries. Admittedly, the vast majority of folks here use 4.2V Li-Ion batteries. So this isn't a huge problem for most. But if you need to charge LiFePO4 and/or want full capacity from 4.35V batteries, the VP2 is the way to go. The LiFePO4 setting is also handy for placing a storage charge on 4.2/4.35V batteries.
3. NiMH charging. The Plus Master will charge NiMH. The VP2 won't. HKJ actually didn't find the Plus Master to be the best NiMH charger in the world. But the fact is that it still CAN charge NiMH and the VP2 CAN'T. This can make a big difference for traveling, since the Plus Master can charge both from a fairly small package (as opposed to carrying a separate Li-Ion and NiMH charger). So if the ability to charge NiMH is important to you, then go with the Plus Master.
4. Charge currents. The VP2 can charge at .25A in addition to .5A and 1.0A. This makes it a better choice if you need to charge small cells like 10440s.
5. Price. The Plus Master is somewhat cheaper than the VP2. Not sure how important this is to you. But it could be a factor for some. On the other hand, Illumination Supply is currently having a pretty good sale on Xtar chargers. So considering that each has its strengrhs and weaknesses, you might consider buying both.
The bottom line? I would say that the VP2 is the better home charger and the Plus Master is the better travel charger.
It is by far the superior Lithium chemistry charger imo over the Master VC2 Plus which only shows an estimated time and percentage of charge, only does 3.7V cells, doesn't have a power bank function, and only has 0.5amp and 1amp charge rates.
Actually, the Plus Master CAN function as a power bank.
