The Rollerblade Spark Pro and Spark 84 are identical apart from styling: they are the same model in effect from 2010 and 2011 respectively. I have both. 84 mm wheels, SG7 bearings, heel brake included. I have read (source http://answers.yahoo.com/question/index?qid=20110327094802AAknInQ) the Spark 84 has bettter lacing and magnesium frame: although I own both I cannot say I really notice a difference. The frames look tinny but no worse than other inline skates at this price point (in the region of £120-130 usually) and in my (not very demanding) use they have not given any problems yet. The tops with removable linings are soft which may mean less control, but they are incredibly comfortable. I bought my first pair at Club Blue Room, and after a lot of attemtion from the assistant there to help me get something which is a good fit, I bought the same size as my shoe size. You can wear them all day and never feel any chance of getting a blister or feeling you will be relieved when you take them off. So for all that they may not meet the demands of advanced skaters, the sheer comfort is a big plus, and I have to say that although I may try hard-sheel skates next time I buy a pair of skates (and in retrospect maybe I should have started in hard-shell skates), I really like this model. General-purpose every-day skating such as I do is supposed to fun: there is no point in have strong responsive skates and being uncomfortable in them. For skates of this type the styling of both is OK IMO, which is also a plus.