Is it normal for a power strip/plugs to have a metallic smell?
Well, the second one has a UL stamp on the front, and usually the Chinese junk makers aren't brazen enough to put that.  But the proof of the pudding is in the File number - a 6 or 7 digit code that should be right under the UL mark either on the packaging, instructions or labeling.  

The first one is on Amazon, and it isn't being sold so it's impossible to see if it's "Shipped from and sold by Amazon.com" or "Sold by XXXXX and fulfilled by Amazon".  The latter is the Amazon Marketplace, which is a cr*pstream of the cheapest junk off Alibaba, barcode stuck on it, and sent to the Amazon warehouse.  Needless to say, none of that stuff has a UL listing with file number.  Both this and stuff direct shipped from China seem to evade Customs.   

Regardless, even a UL-listed item can fail. Exemplars of the item have been fully tested, but that does not mean every production unit is good.  

Power strips should not "smell funny".  And, proof of the pudding, they should definitely not get warm, certainly not with 500W+50W+50W that you describe as your load. 

Needless to say, mains electric is nothing to trifle with.  It is a common source of house fires via shabby appliances, hence the need for UL listings*.  I am very reluctant to use plastic power strips at all, and I hit garage sales and Goodwill looking for metal ones; even a damaged metal one can often be repaired. 



* UL standing for "Underwriter's Laboratories", and "Underwriter" being another name for "insurer" such as the company providing your homeowner's fire insurance.