Just from 35-plus years of experience with four or five different classic car insurance companies over that time span, I have stuck with Tamra and her company MK Insurance for a variety of reasons:
1) They had, by far, the best service.
2) The best rates.
3) They would insure cars that the others would not. They covered my 93 Viper back when other insurance companies wouldn't - like long before it was a (now) 30 year old car.
4) Most importantly, I have had claims under my current policy with Tamra. The no-hassle claims process, superfast payment and expedited supplemental payments, sold me on them.
I have heard nothing but horror stories from people who have tried to make claims under some of the other big-name collector car insurance companies. - for example, one guy had his claim denied because the insurance company said that since he had regular license plates, not collector car plates on his car they wouldn't pay it and in addition, because he wasn't driving directly to or from an actual sponsored car show when his loss occurred - they wouldn't pay. Completely Insane! You really have to read the fine print in a policy before you sign up.
Like I said before, give her a call and get a quote. You have nothing to lose and at least you'll get a $ number for comparison use against similar policy offers from the other vendors.
And no, I have no finanical interest other than harassing her the next time I call to add another car. She did say yesterday when I added my Redeye onto the policy that if they gave out complimentary hats, I would be the first to get one. (So I got that going for me!)