Here's my take on this:
First of all, the ProjectmixI/O and Tascam 1884 are huge desktop controller interfaces so that precludes their use for mobile recording, although they can be mobile in comparison with other mixers.
I wouldn't exactly recommend these large control surfaces for beginners because of their complicated features which can overwhelm a beginner with feature overload. Besides, if this audio interface/controller breaks down, your studio is crippled as a result... I would rather buy separate components to lessen the probability.
The FW-1884 costs $1299 if you look around, the Projectmix is $1249. For that money, I would rather get myself a really good and sweet sounding interface with separate controller. For example, the Mackie Onyx 400F costs $699 if you look around. Other interfaces such as the Focusrite Saffire Pro 26 i/o ($699) will give you 8 channels of Focusrite preamps. Pair that with a Tascam FW-1082 ($599), and you have a very flexible combination that fits within your $1299 budget, and with sweeter sounding preamps to boot! You can even go for more inexpensive controllers such as Presonus' Faderport, Frontier Design Alpha Track, or even Behringer's BCF2000! These 3 controllers go for $199 so you can have enough leftover from your budget for a couple of good mics.