No, not at all! The Lexicon is a LOT better.
A few years ago I tried to use the Intellifex in my guitar-rig at the time(Mesa Triaxis,2:90 and Recto cab)
It messed up the sound and I didn`t like it`s effects that much.
The Lexicon however is really clean and keeps your original signal intact, the reverbs are really wonderful and most of it`s effects are useful. The pedal effects on it is ok, but nothing like the originals.
The G-Major I haven`t tried, but I have used the G-Force a lot, also a wonderful unit. The reverbs isn`t as good as the G2, but still good and it has very good chorus and delays. The Intellifex isn`t even close!
