From the developer:
Obviously this program raises certain issues, the freedom of users to block ads and the way web sites actually make their money which is through advertising. If you feel like trying this program then great, it does remove a lot of ads on web sites and gives you a choice of when you want to see ads. For people with dialup connections this can be a huge difference on their internet experience.
A proxy server is not an easy thing to do, it is actually a very complicated piece of software and SpeedManiac has features like DNS caching using multi-node B-Trees, tight code for speed, 40 simultaneous threads, removal of graphics that meet a certain criteria as set by the user, auto re-sizing of buffers according to file type and
server speed and much more.
When reading reviews, consider the source and any possible reasons behind a terrible review. Decide for yourself.