The RZ is my primary film camera.
If you have a good tripod and cable release, it's great - outdoors on legs is how I use mine 95% of the time. Hiking with it is no problem but I'm a 30yo beefy guy; it might be different if you're 70 and a bit weak at the knees. There are those who'll tell you that a good 4x5" field camera is as easy to transport as an RZ and they're likely right but I can't afford the per-frame costs of 4x5 at the moment, even if I would love to have the movements.
Due to the leaf shutters, it's fantastic for handheld studio flash work because it can sync at 1/400s.
The 110/2.8 and 180/4.5 lenses I can say are fantastic. The 50/4.5 non-ULD has massive field curvature that makes it soft in the corners, so I sold mine after 3 weeks. The 50/4.5 ULD (and 65/4 FL-A) is meant to be much better in that regard but cost 2-3x as much.
The -II version of the body will give you half-stop speed increments while the original is whole stops. I have the original and it's fine for chromes too, you just need to use partial-stops on the aperture setting to get that perfect exposure. I had only one badly-exposed image from the last 3 rolls of Velvia that I put through it.
I would prefer the RZ over the RB: while it is as bulky, it is a little lighter (which matters on a long walk), the electronic timing is accurate and will never drift and the batteries are cheap. They last for so many rolls I don't know the number and I have 3 spares in my bag. You can use a metered prism if you want. The lenses are more modern - floating elements, better coatings, etc. It has a bunch of electronic interlocks (darkslide, film advance, etc) that will prevent common errors you can make with the RB; they've saved me a number of times.
The RB is so much cheaper, you can get a lot more system for your money. I see that as a bit of a false economy though because the amount you'll spend on film and paper will soon eclipse the cost of your camera anyway.