I think it is prudent to waite to which level Zcash will settle and then buy some. I am pretty confident it will be valuable as well - it might even gain official currency status somewhere. The stength of Zcash is its community. Only the super pumped price prevents me from buying some.

For Monero, it is a currency for everyday people and probably chosen by drug dealers and drug addicts. Monero is a decent currency but I am afraid the Zcash has done things better. No, tech is not the most important thing and as we can see from the current system, Zcash type of solution with the brightest minds probably in the world + supposedly a lot of money backing is a way to success, but as I said, personally I would waite until the price settles somewhere and not to go all in. Buying just some in case of it will overtake Monero.

Somebody asked about the GUI, it will probably not be released any time soon (might be that the developers need to rebuy before the release).