I've never used them either but I do know people who have used some and they say they hold an edge better then regular HSS. Weather it is worth the extra money is another question and only you can determine that. Also, the brand will make a difference. All cryogenic tools are not the same just like all HSS or all Carbide are not the same. If you want better feedback you should name the brand you are looking at.
I own at least 8 different brands of tools that run the full range in price and quality. At the low end I have Harbor Freight and Benjamin's Best. At the high end Thompson Tools and Carter & Son. In the middle are Craftsman, Woodriver and Sorby. There are also several brands I have used but don't own. For some tools there isn't a reason to spend the money on a high end tool. It is usually because I don't expect to use it a lot. For tools that I use a lot, such as bowl gouges and certain scrapers, I buy high end.