Hi Barrie,
I fully agree with all of Jason's points.
I have two permanent layouts. Both are 4 lane, and utilise the same DS timing system, with duplicated wiring. One is routed MDF, the other Scalextric Sport Track, repainted with the same ultra smooth masonry paint as used on my routed track.
The biggest advantage with any plexi track system, Scalextric, Ninco etc, is you can change your layout at any time.
It is also easier when putting together a permanent layout, as you can test at all stages of design, and alter things accordingly, where as a routed layout needs to be completed before you get to test it....
I get more issues with power drop on my Scalextric layout. I have soldered the worst offending sections, and also used some of the connectors available from Pendle slot racing. Its nice to have a plexi track, but I don't run anything with magnets in place. Not my type of racing at all. We use Urethane rear tyres, with a bit of ballast weight, and this works fine.
The routed layout has copper tape, which does cause some issues. When it breaks we just solder the joints. Same approach if we have to let in new pieces of tape. I love the way the routed layout drives, so smooth and easy for all levels of competitors. You do need to get the grip level of the track surface sorted. At first I had not enough grip by a long way, it was like driving in the rain....I repainted the track using grey ultra smooth masonry paint, which improved the grip considerably. Keeping the surface clean, and cleaning the rear tyres lots makes a huge difference. As does a drop of Innox on the braids.
It all depends on your skill level of routing your own track. If your happy with that routed does give more options of radius, lane spacing and narrower spaced lane areas.
Good luck with whichever you choose, and ask anything if you want to, the amount of knowledgeable and helpful people on this excellent forum is amazing
Pip