If you go by ratings. The ACU (American Conservative Union) gave Flake a 92% Conservative rating in 2017 (lifetime of 93%), despite all his antics and mouthing off publicly.
Marfa McQueeg, by comparison, has only a 71.73% lifetime Conservative rating. That’s an even LOWER rating than her mentor Cap’n McQueeg’s lifetime rating of 81% (!)
Kelli Ward’s ACU rating in the AZ legislature was a 98% lifetime.
ACU and other ratings can be miss-leading, especially when they only include 20 or so - usually final - votes, as he may vote against or delay a bunch of budgets or resolutions that would have otherwise been more conservative than the final bill. A lot of conservative ratings tend to rank more on chamber of commerce POV rather than mainstream american conservative as well.