Have any of you seen the quality of blade shapening that these units produce? Straight & Mulching? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50377&item=4302431995&rd=1 and http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=4302116045 I have already looked at the Magna-matics and wonder if these will do just as good for a fraction of the cost. I currently use a bench grinder turned around backwards and it works ok but when I sharpen them they dull faster (bad angle) than when I have a repair shop do it. The repair shop does them for $3 each. Any ideas?