This really depends on whether you want to use all the dies available(and which you have probably a collection of!) & embossing folders- in which case the Big Shot Pro is awesome. I got mine because I was fed up with dies getting bigger than my 'bug could manage.Its a big machine though, so storage can be an issue. I did a write-up
HERE on my blog.
The Silhouette is a fantastic machine- I still have my Original Silhouette going strong, after maybe 10 years. I got it when they first launched. The big plus point with them is being able to cut anything from a quarter inch high, to 8". The Cameo also takes 12x12 paper/card. You can cut with any font on your pc, including Dingbats. There are also a wealth of sites out there with free svg files.
UKScrappers is a forum for all these machines. People on there have a lot of expertise with them and are always happy to help a new owner. Also, when you have been a forum member for one month, you have access to thousands of free files members have posted up.
Birdscards is a blog which posts up loads of cutting files, and a Pinterest search for SVG files/ Silhouette files will lead you to many more. I suppose the greatest advantages of the digital cutters are no storage problems for a mounting collection of dies, and the ability to tailor the size you cut out exactly to what fits your project, not just the closest die size to what you actually want. I have to say that the customer service I have always had from Silhouette has been first class-losing all my shapes to a hard drive fail! They store electronically your purchase list, so you can re- download them.
For versatility,( and lack of expense of dies etc) it would have to be the Cameo- I would absolutely not be without mine. Hth.