What battery plate is the best?

Quick answers is whichever one works best for you.  In short, if you do not have the specific need to choose one over the other, it's recommended to go with the more common VMount option.    

99% all units shipped have a battery plate attached with about 75% being VMount.  These batteries are industry standard for broadcast and film industries, so if you already have some, choose whatever you have already.   Removing one more wire makes setups like the Dana Dolly and MYT works sliders, completely cable free of "travelers".  This is quite convenient and way better than putting a battery inside the spectrum for the reasons here.

Does choosing a battery plate limit my external power options?  

No. We still retain a 2.1 x 5.5 barrel connector on the ST4 and all units ship with an AC adapter that can plug into this unit.  Additionally common battery packs can be connected to this port.

If I plug in both a VMount Battery and an external power source, what happens? 

A bus full of puppies explodes. It is bad. Well that was a prototype version and it was messy.  This is why we don't support users do a DIY retrofit of a battery plate.

In spectrum, we use an internal switch to have the spectrum take power only from the barrel connector when something is plugged into that port.  This prevents your 14-16Volt battery from being backcharged from a 24 volt power supply, or a battery injecting current into a 12Volt wall supply, or 12 volt battery.  Hooking up disparate power systems is not a good thing.

What about the D-Tap connectors on the side of the battery plate, can I use them?  Yes, they are powered only from the battery when installed.  You can use this to power a camera or other accessories, but watch out.  This, like other battery plates is unregulated at the voltage of the battery pack so this is good for hooking up cameras or other accessories that you might need to power.

Pro Tip- using a larger VMount or GoldMount battery on the side of the spectrum to:

1. Power the spectrum
2. Power your camera 

 is a great way to reduce the overall weight the spectrum has to support.  Sure, your run times will be lower as many cameras are power hogs and really suck down the packs, but for many shoots, this is a way to simplify setup and put a larger camera / lens combination on there. 

Could you do it in reverse and just mount a battery to the camera and DTAP power to the spectrum?  Yes, but putting more weight where your camera is mounted affects the stability more than putting weight on the very strong tilt arm.