Strobes are usually more dependent on high current than on voltage. And NiMh cells can always provide higher current than alkaline cells, so the strobe makers usually are targeting that and the voltage difference is accommodated in the design.
On cycling and memory effects? SAFT owns the NiCad trademark. They're battery experts for a long time now. Back in the 80's I spoke to one of their engineers, and he said very plainly, the old technologies sometimes had memory effects, but THEIR batteries no longer had them, at all. And the same thing applies to NiMh. No issue at all--in good brands. These days it is harder to find a real engineer to get real answers from.
But I'd beware Amazon batteries. Amazon doesn't make anything, really. And the contract for batteries (in Costso, WalMart, Sam's Club, etc. as well) is usually put out for bids every year or two, and the lowest bidder gets to stick the brand label on their product. So you never know what product you are getting, unless you have current research. Personally I tried the AB batteries three years ago. Wound up sending a dozen AAA back to Amazon because after a year they were not holding a charge well. The AA were working fairly well, but nowhere near the Eneloops I was also using.
When GPS was a new and power hungry thing, I used NiMh AA's from several brands to feed my first GPS. Found that some brands would die in as little as 30 days after charging, but that Panasonic's bulk cells (green plastic wrapper, not sold in retail stores) could sit for six months and still have 2/3 of their charge.
So there are real differences, and buying a "contract re-labeled" battery us always throwing the dice, even if the vendor has a generally good name.
With online sales in general there is another problem of counterfeiting. Anyone can print labels and slap them on cheap products. Case in point, "Ultrafire" branded 18650 LiOn batteries on Amazon and ebay. Literally, every battery from every vendor has been a counterfeit, with minor errors on the label (voltage or amperage rating is off by one digit, color is wrong, etc.) that Ultrafire itself says mean counterfeit.
Duracell also has this problem with online merchants. Last time I called them about some leakers, they said that if there was any Chinese printing on the batteries? They were counterfeit, they'd seen that all too often.
So the vendor's reputation, and the brand name, still do mean something. And with Amazon, of course, if you complain, they'll warranty it.
