I bought one, and it works nicely. I did find that I changed batteries more often than I would like. So I bought a Wahl Peanut. I no longer have to replace batteries which upped the cost over the long term. They both work very well. I prefer the one I plug in. It never failed, that when I had a long seam to rip, the batteries always died before I was done or got so weak that I had to get out a manual ripper to finish. Now, I do not have to keep a big batch of batteries on hand.
The WHAL Peanut cost more at first, but soon pays for it self. Best I have used. I got mine on Amazon or ebay.