I don't own a mini.
I won't be much of a help. I do know the mini has some great free images on it. I would just set that baby up and start playing with the images and CCR. I have seen the mini in action. She does cut wonderfully. The Mini cuts felt and leather so pretty. PC is releasing images off their cartridges as single purchases for only 99 cents. I can't really give any cons since I haven't worked with the mini. I usually do cons for the die cut machines too over here.
A few of the cartridges are good replacements for your metal die cuts if you only use those metal die cuts for paper. That will free up some room for new stamps.
Blogs and YouTube are probably your best bets for the Cricut mini to get your better tutorials.
Your good to go with your 7 pc tool kit. That has you pretty much covered. Watch some videos on you tube how to resticky your Cricut mat. There are several ways to do it. Most of us die cut users have our favorite ways of resticking our mats but they always differ, lol. Oh, I almost forgot the tool kit does not have the spatula. You need the spatula to lift your die cuts off the mat. This is just one of the most important tools in a die cutters arsenal. You don't need the Cricut spatula. I like art palette knives.
My best advice is just play with the mini using the free images it came with. That will give you a good feel if this is a tool you want in your stamp toolbox. Hope that helps.