I've had a pair of poles for months now, always carried them but never really felt the need to use them until recently. I started with a niggling knee injury and took to using one of the poles for extra support, third trip out today using it and I can honestly say it is helping with relieving some of the pressures felt on the knee joint on the downhill stretches and it's also a great aid for those uphill stretches too, once I'm confident that I've got the technique of walking with it perfected I'll introduce the other pole, that way hopefully I won't resemble bambi on ice whilst walking. Have a look at some of the online guides as to how to use the poles to the best advantage, also good tips on how to keep your hands sore and tired free.
Not the cheapest poles out there but well made, sturdy, flick lock system which is a doddle to use (even with gloves on), I bought my Black Diamond Trail Pro poles in a 50% off sale at LD Mountain Centre here in Newcastle, however with hindsight I would say I'd be prepared to pay full price for them should I have to do so again. Personally I wouldn't bother with an anti shock system, just adds more weight to the poles and if you use a good technique you shouldn't need it anyway.