All power drive boosters will reach 10fps irrespective of battery source. What is overlooked is the specific set up that allows this to be achieved. There are a few very, very, very few specific set ups where that will actually be achieved e.g. high ISO film, high response EF lenses (L-series) and fast aperture (e.g. f1.2) conditions that would suit occasions of wildlife behaviour, motor racing (e.g. trace-shooting an accident) etc. For anybody else including legions of hobbyists, it can be a penalising investment in additional weight, even if it provides more reliable secondary power source than the patently lousy 2CR5 batteries even then only proven with persistent, heavy shooting. This is the guiding philosophy of why I had a power drive booster E1 fitted to my EOS 1N choice and enhanced reliability of battery power, not the fact that in an ideal set up it will easily chew through 36 exposures in about 3.4 seconds (the average is 3.8sec), except I don't have (and don't want) any of the ultra-fast (in terms of aperture and response speed) L-series lenses to achieve that.
I concur with the comment on avoiding used batteries; this can be a bad strategy unless you know the history of the battery's use, recharging and storage. B&H will probably ship the battery back by surface (sea mail); read their Shipping Restrictions about batteries. They specifically state lithium batteries will not be shipped by air, but I don't know about rechargeables of any sort.