I have a sizzix big shot that I have had for a year and used 5-6 times (I even bought the expensive strip die cutter!)
The reason I dont like it is that you have to roughly cut your fabric to the size of the die anyway and there is a lot of fabric wastage. It also works out quite expensive to buy each die so you end up questioning if you will use it again (especially as they are bulky storage wise).
I have just got the cricut maker in November and I love it but it wont be for everyone. I love it as there is no fabric wastage (you can make a while 'sheet' of the same or different shapes. Although you can only cut one layer of fabric you cut more shapes overall each time. You are also not restricted by dies and can custom cut whatever you want. Mh net aim is to use it for a more complicated applique project. You can also use it for hundreds of other uses. I'm loving the fact I can cut vinyl to personalise bags or other things that I make.
However, it definitely requires you to be more tech-savvy than the other options mentioned and because it can cut a lot more I am finding myself interested in new crafts as well...