Get the real deal:
Either an FMF Power Programmer or a Power Commander.
Worth the dough because it improves throttle response (meaning when you open the gas, you say to yourself, "Hey, that feels a lot better because it feels more precise and powerful. What a country", and gives you more power at the same time.
I've tried my WR-250R back-to-back with the stock fueling mapping and with my Power Commander lll and with my FMF Power Programmer.
Both of these units were unmistakably better for how the bike ran and responded to the throttle - the stock settings are a severe compromise in order to pass insane EPA regulations and not meant for good performance.
Those cheapie supposed solutions are just another case of you get what you pay for, if it sounds too good to be true it probably is, etc. :)