This tremolo sounds great. The triangle wave sounds similar to a vintage Fender amp tremolo - it's very smooth and refined modulation to give your signal a bit of a flutter. The square wave produces are more intense pulsating modulation that, as you turn the intensity up, will eventually become a full on-off-on helicopter tremolo like in the intro to Green Day's Boulevard....
Yes there is a volume boost with the unit. By its nature tremolo is an effect which causes a perceived volume loss - the fluctuation of the amplitude of the signal causes your ears to hear the effected signal as quieter than the dry signal, when when the the amplitude peaks of the effected signal are just as high as the dry signal. The obvious thing to do at the design stage (which the designers of the Boss TR-2 forgot to do) is to bump up the effected signal to the point where its perceived to be the same as the dry signal by human ears. On this pedal the designers probably took it a little too far - the effected signal sounds noticeably louder than the dry signal, but that bothers me much less than a volume drop would. Actually, the volume boost will ensure no one in the audience misses the fact that you've switched a tremolo on. I haven't noticed any presence boost that a few earlier reviews talk about - my unit seems very tonally transparent. Actually I'd say it falls closer on the side of being warm than bright.
Too early to tell, though it appears solid. I was surprised how light this pedal was. I bought this used but I've noticed Rocktron are packaging their pedals like action figures - in a plastic bubble - like Behringer do. That appeals to the inner child in me (who bought a lot of those figures as a kid) but I think any attempt by them to present an image of the effects as serious and professional (as opposed to disposable toys) is tarnished somewhat by packaging them so.
This is a great little tremolo. It's warm with a good variety of tones and won't break the bank. Better than the Boss TR-2 as it doesn't have a volume drop. It's encouraged me to check out a few more of Rocktron's products, particularly the Hypnotic Flange and the Envelope Follower.