I have had mine for around a month.
It is hands down the best controller I have ever used. (I have used the ART X-15, Lexicon MPX R1, Rocktron All Access...and Line 6 stuff but that doesn't really count.)
I have mine set up with two EB volume pedals as expression controllers and a Boss FL-5 (I believe is the model) for tap.
This controller does everything I can imagine, and then so much more. I had few hiccups when I was setting mine up and Jeff (Mr. Liquid-Foot himself) emailed me very promptly and even called my house to help me. When he called, which he did at my convenience, it seemed like I was the only person on his mind at the time. He let me take all the time I needed and walked me through a lot of programming functions I hadn't learned yet. Jeff takes the product very seriously and listens to people suggestions and bug reports. He fixes bugs as fast as Cliff fixes the Axe firmware, and has added some awesome features suggested by users. The one feature in particular that I love is the layer function, where each Instant Access switch can have 2 functions (Page 0 and Page 1)..so in essence the 16 IA buttons double and you now have 32 !! Before I had the Liquid-Foot I was using the Rocktron and was trying to decide how I wanted to compromise my switching, now I am trying to figure out how I am going to use all the switches. I love it.
To make a short story long...I love the liquid-foot as much (well almost) as the Axe-Fx. It opens up the Axe-Fx to be the most it can be. I don't regret my purchase one bit, and wouldn't hesitate to recommend it to anyone. If you are thinking of spending a couple hundred I would save a few more bucks...if you are thinking of spending a thousand or more...save yourself some money and get the better (IMHO) controller.
The only bummer about the whole thing, is Cliff has stated that the Axe Controller will be the only foot controller that will be able to utilize the Axe-Fx's tuner. I don't know if he will stick to that or not, but I am going to buy the Liquid-Tracks now so I can have a tuner on my board. I guess Cliff is going to force people to buy his controller if they want a tuner on the controller.