I have 2 routed tracks and am beyond needing a starter track, but checked this thread out anyway to see what new folks might be dealing with as I remember getting my first racing sets decades ago.
Someone looking for a Christmas gift might wonder why the price difference and if it's warranted. On the LEB Hobbies website the Carerra set is $116 (discount price) and the Scalextric is $172. My 2 cents worth of advise is the Scalexrtric set has more track and features, especially if you have a tablet and intend to use the ARC One features. I watched the video of Harry's grand daughter running a race and after seeing how comfortable kids are with tablets and apps I foresee hours of fun being had on this set. BUT, if the setup shown in the video and images is of the complete set, the fact that it doesn't come with boarders or a fence for the outside of turns is a big disappointment. Maybe the magnets in the cars make it possible to actually race without boarders or a fence but I think it's still going to be a point of frustration.
The Carerra track, even though just s simple figure 8 at least it has fences and can be raced on. For little ones where it's just going to be set it up, plug it in and let then have at it I'd recommend the Carerra track. If there is an interest in actual racing, using the Arc One features, and expending the set I think the Scalextric set is worth the extra cost - BUT INVEST IN SOME BORDERS or FENCES ASAP!
Slothead