So I purchased 4 different hammers because I couldn't decide which ones I wanted. I looked at PB Swiss, Wiha, Nupla and Halder. Nupla is a large US company and an OEM to many different US tool companies.
First off is the split face Wiha hammer. This is a really nice piece. I purchased the hammer alone and 3 different faces. It was cheaper than buying the whole kit which featured two additional square faces I figured I'd never really use. The only negative thing is the top of the split housing is a large 1/8" gap where dirt can get in and fill up. So it's not something you can just drop down into dirt. Nupla offers screw in ends with more offerings, but the wiha one was cheaper on sale and I preferred the Hickory handle.
The next three hammers are all dead blow. I surely prefer the dead blow after using both in many different situations. More force for longer period of time. The only time you don't want a dead blow is if you're trying to break something rather than move something.
The PB Swiss hammer offers the smallest diameter head at 22mm, and is the nicest in my opinion. It's very light and also a deadblow hammer. Rather than the round pellets of all other deadblow hammers, the PB Swiss has a series of metal washers instead. This keeps the forces going directly in the direction of the hammer making it better to swing. The metal washers are a bit louder than the Wiha, sounding more like a rattle. PB Swiss offers two different caps, a hard nylon and a metal capped. PB Swiss price, but also PB Swiss quality.
Next are two Wiha dead blow hammers, the 25mm and 40mm. The 25mm is very light and the 40mm is too heavy for me. I think a 30 or 35mm would be ideal. The Hickory handles have a light clear coat over them. This should extend the life of the wooden handles, but isn't as natural looking as their split face or the PB hammer. The deadblow pellets are quieter than other deadblow hammers, as some others have mentioned. The negative side is there aren't different ends available, only the medium hard polyurethane ends. At least they are replaceable.
Most companies offer fiberglass shafts or full metal shafts. The wooden handles are lighter, placing more weight on the end. This can be both a positive and a negative. Positive because the hammer is lighter, but negative because the balance point is further away from your hand which can make the hammer harder to control. Of course the soft rubber grips are also nicer, feed less forces back into your hand and won't slip if your hands are sweaty. I think the fiberglass or metal shaft on 35mm or larger dead blows is the way to go, and wooden on the smaller hammers.
You can get the Wiha hammers almost anywhere, but look around for the best price as they do vary. I'm likely going to sell my two Wiha deadblow and get another PB Swiss. For PB Swiss there are very few dealers in the US. I bought mine from Tool Lady, who upon reference will provide first time buyers a 10% discount, just tell them Chris Brown sent you.