I started with an online rate aggregator that just produces soft estimates, then got real quotes from the top couple.
I found the rates to mostly be very close, and ended up going with a company that already services my pension for convenience.
One point someone raised when I was thinking about it is that for a person who is building a solid nest egg, your window of risk is relatively short because eventually you just have money. So what you really need to cover is your period when you're building your nest egg. Once you have seven figures in the bank, you probably don't need insurance. If you die, your spouse/kids will be fine living on the savings.
Going with a shorter term like 10 or 15 years will get you a much better rate than 25 or 30 years. Mortuary tables and all that.