The D9 wireless is my primary (I love having all the info right in front of me with one less hose). I also use a Vyper as a back up when I'm doing liveaboards or multiple dives per day. I'm glad I've done this too because on my last liveaboard trip, during a SI, I just took a swim off the boat. I was still wearing the D9 and it went into shock and locked me out from diving!! From what I surmised it did this because I didn't turn dive mode off where the computer would have allowed me to swim and not consider it a freedive and penalize me for it. However, since I had the Vyper as a backup on all my previous dives that day, I was still able to dive and not worry about my saturation levels - I just attached a spare SPG. Not to mention, the captain would not have let me dove for 24hrs if I didn't have this backup. That would have been an expensive lost day.
Suunto's great. Wireless is fantastic. Over 50 dives with no transmitting problems.