I don't know that model number, but Stihl makes the best. Mine is over 20 years old, and still sawing.
It does echo - just very quietly. I know - I've heard them! This has been proved on "MythBusters" and "Braniac: Science Abuse", who both found that, when examined by an audio-expert, the echo was "swallowed" by the original quack, due to the very sim...
You could trim them yourself for free. I have to wrap my bunny in a blanket and I use my cat's nail trimmers. Make sure not to go far enough down to cut the quick. Don't want any bloody nails. I don't believe it should be over $10 though.