It isn't in my opinion. You may be unfortunate enough to have a software conflict which it is unlikely that I will be able to assist with. Most users don't experience problems with speed (feel free to contradict me on this, I want to know!). I will be adding a feature which will record the response times which you can compare with the regular interface by using a program such as IEWatch which can be found at
http://www.iewatch.com. I used this tool to help develop this program.
Also don't forget that the program is contacting the same Betfair servers as the regular interface so if the site is experiencing difficulties, so will this program. Check the Betfair forums and see if people are complaining!