I would definitely make sure the battery is healthy before you run it.
It's hard to overstate the benefits of speed control. Protosound 2.0 can force a loco to run much slower than it otherwise would. The sound is also improved over Proto-1, and the announcements, special sound sequences, etc., contain some fun surprises. But the added hardware and complexity can hurt reliability. The early 5-volt systems are more trouble-prone than later version. If your electronics are DOA there's an upgrade path -- for a little while, anyhow -- but it won't be cheap.
Proto-2 also allows individual control of two locomotives on the same track using DCS. That's another chapter. Personally I'm not a fan of DCS, but if you achieve success it adds a fun operating dimension and obviates much of the need for block wiring, control panels, etc. Good luck with your noew train!
