There's not much difference between USBSR and Zentimo IMO (http://zentimo.com/zentimovsusbsr.htm).
They gave Zentimo away for free some week ago (http://zentimo.com/giveawayd11.htm). Missed that. Well, they had free giveaway of USBSR and Zentimo all the time, I'm sure there'll be another giveaway.
you're right on both matters but ultimately Zentimo is supposed to be the companies all-in-one-all-singing-and-dancing USB (& SATA) control toolkit.
As I sort of indicated USB Safely Remove is mature (and years old) at version 5.x, but Zentimo is only 2 years old and version 1.5x at present but BOTH products do continue to constantly develop
Having said that, I have seen some other excellent USB applications about the interwebs worth consideration.
I believe I've read Zentimo & USB Safely Remove BLOG comments asking things like: "why do do keep giving away Freebies on sites such as GOTD when I've paid good money for a license" & Igor Tkachenko (the chief developer) usually answers with the following paraphrased responces: it increases the user base, gets feedback regards compatibility and errors as well as feature requests and some of the Freebie owners try and then later buy.
Igor (I.M.H.O.) really prefers people to take the subscription model and has given some dreadfully lame answers when people asked about the Zentimo 'Lifetime License" purchase option removal such as: you cant give a LiFETIME license when the company may not exist forever and other such crazy answers but the fact remained that USB Safely Remove was still being offered with an L.L. and Yet the same company wasn't offering L.L. for Zentimo which didn't seem fair especially as a group of owners who "bought in" to Zentimo when it was a fledgling product did have L.L. and would never have to pay anymore money.
It would seem obvious to most rational people, that when they buy software with a 'Lifetime' license the term "means for the life of the product" but IGOR used to imply that it meant 'for the life of the owner' which of course was utter codswallop. Plenty of software programs reach their "zenith" were further updates would be tinkering for no real reason and ultimately a waste of resources, for example: Anvir Task Manager Pro
v6.3.1 didn't release an update for almost 2 years (v6.5.x was released in Feb. 2012) and "some" buyers complained and felt they'd wasted their money as updates weren't being released, but many more reasonable people were happy that they had a "stable" program which didn't require updating and they knew they could always email for support at anytime if a problem occurred.
Anyways after that small digression the point of my comments is a "heads up" to many owners that at this moment in time, at last the Zentimo L.L. is a purchase option again, and, as it includes free major upgrades as well as the usual free minor updates, the L.L. purchase option is for most people 'the best value for money' license option that CrystalRich dot com offer (and to previous "paid owners" of Zentimo or USB.S.R. will almost certainly be discounted from the face value price)