this topic was dealt with earlier. we have our own imminst brainbuilder training program running at www.mybraintrainer.com
i've spent a bit of time working on the exercises, but given that they're elementary cognitive tasks (ECTs) i have reservations about how they'll improve cognitive ability.
at the very most i think it may improve attentional abilities because of the reaction time aspect of the tasks, but i don't think that this is anything that one couldn't derive from meditation or even just playing computer games.
there's an article at braintrainer discussing an alleged study looking at the use of their tasks and improvements in IQ. i don't want to sound nasty but there's something fishy about it all because the man who did the study allegedly passed away, and so the webmaster doesn't have the full-length paper available for viewing. the site and community there is great, but if the tasks are worthless then you're just wasting your time.
www.brainbuilder.com have better tasks i think, they focus more upon digit and letter span (both visual and auditory presentation) whose benefits make a lot more theoretical sense. these tasks have higher correlations with g, and load heavily upon working memory capacity. they also have a free 7 day membership, i recommend you all check it out.
in other words, there was no point to this thread, just aimless rambling