This sounds like a number of Kitchen Aid stand mixers in both the 500 and 600 series, but it's both 5 qts and 475 watts. Sams may well have contracted with Kitchen Aid though to make a particular combination of quarts/watts/features/etc just to be sold in their stores (I also didn't see that particular model or combo of features at the Kitchen Aid website).
At any rate, all Kitchen Aid stand mixers are very very good in terms of what they'll do, sturdiness and reliability, etc, so any that you'd find at a good price (under $300-325) would be *much* better than not having a Kitchen Aid stand mixer if you do a lot of baking, etc,, and an excellent investment over the years.
Looks like this one comes without the "pouring shield" but that's really not necessary and pretty sure you could purchase one separately if you ever felt you'd use it a lot.
I also can't tell if there's a handle-end on the lift handle like other KA lift models, and don't know if that would matter.
This model is one of their "newer" types over the last few years though (has a lift rather than head-tilt, no ceramic coating on the paddles, may have a different sound at higher speeds--higher-pitched, louder--, may be a bit lighter weight, etc). As mentioned though, they ALL are good.
The Sam's Club website page for this item:
http://www.samsclub.com/sams/kitchenaid-professional-hd-stand-mixer-black/prod8140012.ip
shows that your model gets almost 5 out of 5 stars from 611 customer reviewers. Not sure how that could be better.
http://www.samsclub.com/sams/kitchenaid-professional-hd-stand-mixer-black/prod8140012.ip#tabRatings (you can also "sort the member reviews" for all those in various ways if you want...read through a bunch of them to get all the pros and any cons, but be aware that some people have never had this kind of mixer before and may may make complaints about things that aren't warranted)
This cobalt blue one at Amazon looks like perhaps the same model, but no reviews yet:
http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Dgarden&field-keywords=KitchenAid%20Professional%20Heavy%20Duty%205QT%20Bowl%20Lift%20Stand%20mixer%20475%20watts
You can find various Kitchen Aid stand mixers online, and sometimes at local sales, for good prices too, and some online ones don't even charge shipping (which can be a lot).
Here's one place for example, but even eBay has them (and KA mixers can all last 30 years or more, even if buying an old one):
http://www.everythingkitchens.com/kitchenaid-mixer-sale-8.html?gclid=CJSZ9uDY5sECFUiGfgodmZoAiQ
.