Does the cubika have the crema-enhancing gadget in the basket? That's there to make sure you get some semblance of crema whatever stale incorrectly ground coffee joe public puts in the machine. It will prevent you getting a thick dark crema and properly extracted shot if you're using good technique so the first job is to bin it and get a regular basket.
Classic is best because it has an adjustable over-pressure valve, a three-way solenoid and heavier brass grouphead and portafilter. Info about all that stuff is on google.
That's not to say you can't get decent results from the Cubika, it's just more difficult. Lots of practise, reading, and a good grinder are required. A Rancilio Silvia steam wand will make microfoam a possibility.
It'll be a lot of fun learning though, and when you master that machine you will have a better understanding of temperature management and extraction than someone learning on a commercial machine.
see fig 1
fig 1