We've had our RZ4 for two years, and we love it. The pictures shown above are from our boat. Obviously, for very tall people, the Alpha Z tower can be a little short. I am 5'9" and it works great for me, but if you are over 6' tall, I would suggest that you get a chance to experience it for yourself and decide if it may be too short for you. The tower is solid, with little to no rattles, and a lot of nice features built into it. A couple of limitations for this tower, however, are the board rack mounting points and the speaker mounting points. If you will want to mount more than one board rack per side, or if you want to use tower speakers other than WetSounds Pro-60x, Pro-80x, or MB-8x, than it would require some extra thought and special effort to make it work. For my family, it has offered everthing we needed in a tower. If you live somewhere that a bimini is critical (like for us on Lake Mead), I suggest getting the extended bimini. The extra 2' of bimini coverage is nice, as the basic bimini is only about 6' long.
Ours has the standard PCM 343 engine, which has plenty of power for us. For those running a lot of ballast, re-propping from the stock ACME 537 to something like the 1235 will be helpful without needing to upgrade to the larger PCM engine. I think that only folks running huge amounts of ballast need to consider the larger engine. Our PCM 343 has been reliable, but did need to have a fuel pump replaced under warranty.
For the ballast, I think the Pro Ballast option will give plenty of wake for beginner/intermediate boarding and surfing. Plus, if you find that you want more, the rear sacs can be easily swapped out with larger ones. The extra front weight the Pro option gives over the Surf option would be beneficial.
The factory stereo options are great, and should satisfy the majority of people. The Tower of Power option, with 1700 watts and all WetSounds components (except Clarion HU) sounds great and can give really good sound straight from the factory. Sure, some buyers will still want more, but I don't think you'll find a better factory setup. We did install a WS-420 on ours, and pulled the XS-10FA sub for an XS-12.
In my opinion, overall build quality on ours was good. Some minor issues, but those were resolved by the dealer in short order. I will admit, however, that I don't have much experience on brand new boats from other manufacturers, so I don't have a basis to compare.
All things considered, we are extremely happy with our choice of the RZ4. If I knew then what I know now, I would look closely at the RZ2 as well, since we really haven't needed all the space the RZ4 provides. But, my wife really loves having a huge boat with tons of room, so I don't know if the final decision would be any different. The women and kids always gravitate to the bow in our boat, so the large picklefork bow area has been well used and appreciated. Finally, here are a few exterior pictures. This was the same color scheme used for Tige's 2009 promo shots, so you have probably seen it before.