I own and use an L-758DR every day of the week. It's one of the best tools and investments I could have made for my studio and lighting kit. It's accurate and consistent and offers a feature set that is fabulous.
As Rich pointed out, you have the luxury of going between incident and reflective spot metering quickly and easily without removing or exchanging components. The LED viewfinder is great and 1 degree spot metering is fantastic because it enables you to take meter reading from a distance and maintain accuracy. When rendering backgrounds black or white all the guesswork is gone and you can meter from camera position and it saves you a lot of running around.
The averaging function is nice and very helpful if you working with or learning the Zone System. Of course, seamless integration with Pocket Wizards for remote triggering and metering is a beautiful thing. If you're using Pocket Wizard Multi Max's you can even take advantage of selective quad triggering for different zones or shooting locations in a large studio.
Calibration an be handled on a few levels, ranging from global calibration to independent calibration of incident and reflective for flash or ambient as well as going to the extent of establishing a custom profile for every mode and every ISO with the ability to have 3 presets that can be used for different cameras, lenses or anything you wish.
Battery life is quite good with the CR-123(A) and even though wireless triggering of Pocket Wizards uses a lot more power for the transmitter, I still find battery life to be very good.... but I do always make sure I keep a spare battery in the little holder inside the case.
I don't know what's around the corner in terms of light meters but in my opinion the L-758DR is the Porsche (or Rolls Royce if you prefer) of meters. It does everything, it does it well and I can't think of anything it doesn't offer that I could want. I can't think of anything negative to say about this meter.