It seems good value at £3.99 a month compared to a Sky sub and has the full season of World Superbikes plus most of the top cycle races and plenty of motor events. I'm assuming you get unlimited access to all programs on the channel?
Been using it for nearly a year, mainly for the cycling but the car stuff is a bonus. Excellent service and yes you get two channels all the time and sometimes more, alternate tables at snooker or courts at tennis etc. Lots of videos to watch of past events too.
We watch it mainly on internet connected TV (Panasonic Viera) but seems good when I've tried it on Ipad and Win' PC. We have fairly fast b/band (20Mb) and hardly ever see buffering but I would hesitate to recommend it to anyone on a slow connection.
Its actually not the speed of your connection, its the potential for contention.
Since about 7:00pm is considered the worst (beginning of the soaps, key relaxation time) then you should try it at that time. If its OK then, you are probably OK always.