I'm a little leary because I bought a few items from iChameleon (I think they changed names) via a Mamapedia deal and the quality wasn't great. I haven't tried PlumDistrict at all yet. I buy from Zulilly (which has a no refund policy - it's all clearance) and have had no problems with them, though sometimes the price isn't the deal presented (I can buy the same toy elsewhere for a similar price, for example). Totsy, who was once associated with Mamasource/Mamapedia was terrible. I had to cancel a card to get them to stop charging me for an item they admitted they could not send me. I've used several Mamasource coupons with no problems, including many magazines for children. Not entirely thrilled that Mamasource gave them my email addresses so they can now spam me, though.
ETA: I was just about to post that link. IMO, they are right on target with their reviews, so buyer beware.