I've got ACE - had one claim (theft of electronics) which was handled promptly and fairly. This question comes up not infrequently here on TF and ACE and Charter Lakes consistently get the highest recommendations.
I dont know what state you are in or if it is available but I have erie and they are incredible. I have a 2005 parker and the rates were lower then any I could find at the time. They offer full replacement which is awesome. I have actually had a claim that required full replacement of a high end lawn mower and they were very prompt and paid out no hassle