The difference is the price only.
355630
I can not notice any difference in the print quality between these cheap ink cartridges and the brother cartridges. The only difference is the price which is significant!
3721710
There is a difference with it installed but I expected the difference to be more. But have only had it installed for a couple of weeks so far.
3900142
My review was based on purchase of this item at a MUCH LOWER PRICE.  In October of 2011 I bought 10 of them at a price of $1.99 each, with free shipping. It's not right to apply my five-star review to a different offering of the product, which costs 4 times as much.  Just not right, I tell you.  The original review shows how important the price was:

The old mains-powered always-on exit signs use two bulbs, and they are now close to $5 each at the local hardware store.  And they don't last very long (typically around 4 months I think) so that's a big chunk of the maintenance budget.  Only comparable ones I found were 40W, which causes a different problem.  Mostly LED signs have been used for the last 10 years or so, but that is an expensive conversion--  sure, conversion cost is offset by low running cost eventually, but I'm in rented premises for only another three months. Supplier is good, efficient, and a pleasure to deal with.
2296722
Better than paying half-again the price for the same item.
2066660
Quality no difference with other brands, just a little pricy
1703413
If it was one or the other it would either be a fantastic or terrible deal.  Since it is both cheap and inexpensive, it is just what it is.
4746853
Pay more for the factory version or get these and save.  Could find very little difference in the two.
278659
One of the bars  is open :( and the average price per bar is about the same with the price if you buy them individually
1085494
The same part as on B&D's website only cheaper; what's not to like?
390144
Get it - you don't need a pricey version of the same thing.
3197922
Just what it says it is, but times two because you get two of them in the deal.
4038279
Same price as store. There doesn't seem to be an advantage here. When I am at Office Depot I will just as easily purchase them there,
1020092
Purposely meant to be misleading, be sure to read completely. You do only get one button that others are selling for 2/3rds less.
277719
Not the US  version, despite the premium price.
4725692
Pros: the price!
Cons: they are a little thinner than ones that I got from Jos A Banks, but can be doubled up if necessary (I haven't had to but Im not picky about those kinds of things). Given the price difference between the two, even if you double up, its a considerably better deal.
3578119
A lot less expensive than going to the manufacturer, it worked with only a slight modification.
4919351
I like the product, but would be happier if the price were lower.