I use them daily and am writing one. They depend greatly on the power and flexibility of target language. Most do a terrible job at preserving comments and don’t try and do well on simple code. The better ones give up when they find something they don’t understand or do a partial translation leaving the original code as a comment. The bad ones just translate to garbage that will not compile. On evolving languages like C# translators have trouble keeping up. On dead languages they are usually very good and going to C# is a plus since it is very powerful and has many features you need.