Hi Kate,
If you're looking for unbiased "Consumer Reports" type reviews, none have been performed for any spa brand. Other sites that rate spas sell the rating and are not to viewed as unbiased. What you will generally find here is advice to wet test any brand in which you have an interest and perhaps a few others before deciding on a spa. Make sure you are comfortable with the dealer. The rap on Master has to do with an unscrupulous rebate "cash voucher" scheme, not the spa itself. The spa brand itself has some followers here, but isn't heavily represented from what I've seen.