I just got mine yesterday.
Its relatively cheap, face it 350 - 400 bucks for audio equipment is pretty minimal. Considering some people will drop that and more for a cable, its not an "expensive" addition to your system.
I have an NAD T175, adcom 7.1 power amp, Dali Helicons.
The addition of the iTransport is great, and I feel it was worth it.
Why do I like it?
First and foremost, the internal dac on an ipod blows. The high end has that annoying A.M. radio sound. Many folks want 10,000,000,000,000 songs or so on their pod and record at low bit rates. They can save their money. If you don't import to the ipod in very high wav or lossless, just get a regular dock or plug into your amp through the headphone jack. You won't miss anything and you can save your money for a 1000 gig ipod for more stomped on files.
If you have true high bit rate files, and you care about playback quality, the iTransport is plain awesome. The high end is smooth and pleasant, there is no "sizz" that gives you a headache and really ruins the experience (for me at least).
I have used BOTH the analog outputs (which bypass the noisy volume stage of the ipod) and the digital spdif cable into my NAD. BOTH sound really good. One thing that may help is that I am using Kimber Hero cables on the analog output. They could make a big difference, I can only tell you that both the analog and full digital output are really, really, great sounding. The digital spdif cable is a mass produced "convenience" that they included (nicely) in the box so that you could use it right away. That being said, the manual even says its not top quality - and that there are many better cables out there - I will be getting one and let you know.
I have the ipod Video. Does it suck that the menu disappears? We'll, yeah I guess I would rather have the menus. That being said, I am working on playlists, and can play albums, artists, shuffles, whatever. I was told by an audio dealer that Apple is working on a compatible firmware upgrade. If they get it done great, if not, I am not going to lose any sleep.
Some people call the iTransport "big". Big is a relative term. This thing is 1/4 the size of the smallest piece of audio equipment I have. The case looks nice to me, the isolating legs are cool. The back panel is a littly flimsy, but thats my only criticism. Also, the manual is written in a sort of "pseudo apple" simpleton fashion. It has its purpose I guess.
Those product bashers are a little harsh in my opinion. I am not going to get heavy handed wit the keyboard, but take it from me, this thing BLOWS AWAY any ipod dock that you could buy up until it came out. As long as you have full bitrate data, and a good system to play it through, get it! 350 bucks is a good deal for what it does - I have approx 700 albums in my pod, now I can FINALLY enjoy them in full color without getting out of my chair.
I have to go now - to sit on my duff and enjoy the wadia some more :-)
Plain and simple - the sound is very, very nice.