Spending the extra $100 on this version doesn't seem to make any sense. I like to keep my barometric altimeter on my wristwatch, my compass on my sighting-mirror magnetic unit, and my thermometer in my snowpit kit. Constantly taking out my avalanche beacon to reference navigational functions has no appeal to me, and even strikes me as potentially dangerous (e.g., if a slide were to hit as the beacon were dangling about outside its harness).
See my full review of the regular version here:
http://www.wildsnow.com/1677/pieps-dsp-beacon-review/

This is a great beacon. I was able to try it next to some other brands and personally found the Pieps easier to use, more intuitive, and great for multiple burials. I personally recommend the base model, since I don't have a lot of interest in pulling out my beacon to check the compass, temperature, or altitude when I can use a watch for that. With or without the upgrade, the Pieps is a solid beacon.

If you really want to find someone fast with no confusion, this is the beacon. Skip the compass,temp and alt, if you want to save money but don't buy a beacon without three antenna's. The Orto S1 might have a chance at topping this if they had only put in three antenna. (I think they did not have space and by the time they figured out the real advantages of three antenna in completely eliminating false maximas they did not have room so they came out with the d3 and the patroller which are limited in multiple burials and range) The next closest competitor is the Mammut if it only had better range. It says 60 meters but I often get morning range checks into the 80's.

I have used most other beacons except the new Ortovox and have been delighted at the Pieps ease of use and their reliability. Best range of all currently available, especially when tested with other popular brands BUT who in their right minds would be getting out their beacon from its secure location every 500m to check altitude and compass heading? This is surely a big time marketing gimmick. A better add on would be a 457mHz PLB or GPS.

The recent findings that a small magnet will switch this beacon from transmit to receive and even off because Piep's uses a magnetic switch inside the beacon makes this beacon a liability for the owners and users of this tool. It also has ghosting issues with older analog beacons perhaps because it narrowed it's bandwidth to increase it's range of find. Lastly because it is not downward compatible with all other beacons on the market it is not a valid tool for avalanche rescue and the software should be redesigned to meet industry standards where a new beacon reads and recognizes all other beacon on the market.
A side note-in beacon trials in the field this beacon came in last for ease of use and speed to find victims, if at all, considering the issues it has with older analog beacons.