You don't need to know all that much in order to use the Alto Alphaverb, as it's pretty simple piece of gear, which I don't think is an accident at all. It's got sixteen different preset effects to choose from, the majority of which are for different types of reverbs. It's also got parameters for setting the input, output, and mix levels. A manual shouldn't be necessary considering how simple a make up this is.
While not awful, the general sound of the Alto Alphaverb isn't anything to write home about. I definitely wouldn't use it in a professional studio environment, but in a home studio setting you can probably get away with it. Even so, I've heard many reverb and other effects plug-ins out there that sound better than this that I would rather use for both convenience and quality. I will say that the reverbs are probably the most realistic on here, along with the chorus, flanger, and rotary effects. While this is a quick and easy way to get some effects, it's still easier to use a plug-in. However, if you're in a live sound setting, this is a good way to get some simple digital effects for a cheap price.
If you're looking for a multi effects hardware processor, the Alto Alphaverb will do the job more times than not, but there are definitely better options out there. If you're looking for a something for your home studio, this will work, but I'd highly encourage you to go the plug-in route as it's easier in the end and will give you much more flexibility. You can definitely get a decent multi effects plug-in for this same price...