The Epson WorkForce Pro GT-S55 is almost identical to its predecessor, the WorkForce Pro GT-S50. In fact, according to Epson’s own spec sheet (pdf), there is only one difference: ultrasonic double-feed detection.
Otherwise, the GT-S55 and GT-S50 are the same scanner. So, instead of doing a full review of the GT-S55, let’s just decide whether ultrasonic double-feed detection is worth $170, because that is the approximate difference in price between the two scanners on Amazon.
Correction: As far as I can tell, there is actually no difference between the GT-S50 and the GT-S55 on specs. I misread the above-linked spec sheet, which actually compares the GT-S50 to the GT-S80. If you want ultrasonic double-feed detection, you will need to get the GT-S80.
Ultrasonic double-feed detection
First, what is ultrasonic double-feed detection, and why might you want it? On the one hand, it is exactly what it sounds like: a fancy way to figure out whether the scanner has sucked in two pages at the same time. If you want a more detailed explanation, this dynamic fellow has a gripping explanation on YouTube. From what I can tell, it is sort of like putting a tiny dolphin inside your scanner that chirps every time it detects more than one page with its ultrasonic super-powers. (I should commission the The Oatmeal guy to draw a picture of that.)
My first document scanner, a ScanSnap S500, did not have any kind of double-feed detection. Knowing that, I usually counted the number of pages before I scanned and checked to make sure the same number of pages were actually scanned. This kind of double-checking is fine for small documents, but incredibly inconvenient when you have a stack of discovery documents to get through. After a while of not finding any double-feeds, I grew to trust the scanner. So I stopped double-checking. Then the inevitable happened: I found a scanned document with a page missing. Shortly afterward, I started noticing my scanner picking up two pages at a time fairly often. I replaced the paper-picking assembly and started double-checking again (and added a 7-day “buffer” bin to my scanning workflow), but I stopped relying on that scanner shortly afterward.
Then I got an S1500, which came with ultrasonic double-feed detection. It worked like a charm (although the interface for correcting double-feeds was inscrutable), so I stopped worrying about double-feeds, and just scanned happily along.
So is ultrasonic double-feed detection worth the extra cost?
The fear of going back to constantly wondering whether I would one day open up an0ther document only to find a missing page — probably the missing page — is not worth saving $176. Not to me, anyway. I would absolutely spring for the more-expensive Epson WorkForce Pro GT-S55. If scanner reliability is mission-critical (i.e., you are going paperless in any significant measure), you’ll want the double-feed detection, too.
Who should buy the Epson WorkForce Pro GT-S55?
As with the GT-S50, the GT-S55 is a solid, reliable document scanner with TWAIN support. However, take the TWAIN support out of the equation, and the ScanSnap S1500 — and now the iX500 — is a better option. The scanner is easier to use, the software is more intuitive and flexible, and the ScanSnap is just a better all-around package. Unless you need TWAIN.
So if you don’t need TWAIN (i.e., you do not know what TWAIN is), get a ScanSnap. However, if you do want TWAIN, the GT-S55 is probably the best choice.
And, I suppose, if you don’t care whether you miss a page now and then, go ahead and save a few bucks on the GT-S50.