Austen is correct. It's all about power first. The very first question you wanna ask yourself is "what do I plan to cut or etch?"
That question will determine the power range you want to go with. Etching on a soft wood can be done with a 40 Watt. Cutting balsa wood or thick paper can be done with a 40-50 Watt. Thicker wood/plastic cutting requires a 60 Watt. Cutting metal......well, let's just say it's really expensive.
And even the power ratings that you may read (eq. chinese machines) can be exaggerated. A 60 Watt is actually a 50 Watt.
And finally, a 60 Watt is approx 1m in length, usually along the back edge of the machine. Lower power have tubes that are shorter. So where will your cutter fit in your shop?
So again ask yourself....what exactly do you want to cut or etch?
Technique? The software isn't a real major factor. It's trail and error on the machine you working on.
That's my 2 cents.