It's a good preamp. I had one for years. Only sold it because I didn't use it much, and a friend kept asking to buy it. I liked it. It just depends on what you're looking for tonewise. It sounds clean, has a nice EQ, definitely has the Eden tone.
Great Eden tone in a box. Plain and simple. I used mine with a Sansamp clone and it always sounded great. Pretty touchy EQ and power supply requirements, IIRC.
I would definitely use another one if I needed that particular sound. My clean tone needs evolved past the WTDI.
I don't gig without it in my case. It saved my ass on one gig when my amp died because a sound guy (drunk) fed it phantom power. Very useful in the studio too.
I just purchased one last month and it sounds great. Plays clean, the EQ works great, and it sounds like the Eden amps I have tried. Couldn't be happier with it!