Whynter is the longer standing brand. More have used them with success and the pricing reflects that.
Costway is a brand like a number of others that have shown up in the last year or so. They have not had as long to build a reputation but a lot of people are buying the lessor brands due to being more affordable.
In both cases the vast number of reviews are positive with a handful of 1 star "it didn't work" reviews.
I think one thing in favor of the Whynter is that you can return it to Home Depot should you need too.
Personally I am hoping that the lessor brands hold their own and get a chance to prove themselves. The market has been dominated by three brands until now and they are not all that affordable. Now there are a few smaller units under $200 which would pay for themselves vs the cost of ice in a relatively short time for those with smaller budgets. This might even cause the big three to lower their prices.
