Our original Kenda Kwest front tire failed today due to an unknown
outside puncture during a ride. Having just been reading about the
wonders of Schwalbe Marathon tires, and finding one in stock in the
same (406: 20" x 1.5") size at our local Sun dealer, I chose that for
the replacement. The key difference is that the Marathon can accept up
to 100 PSI, as opposed to the 65PSI max of the original tire. It also
has a kevlar belt and night-reflective band all around the tire that
may add a bit of safety & longevity.

Installation was no problem, and apart from rolling resistance seeming
a bit lower at the higher pressure, the new tire seems to work just
like the old one, with a very similar tread pattern.

The Marathon is also available in a slick version, which I have and
very much like on my Dahon Jetstream P8 folding full-suspension bike.
I suspect it would have enough less rolling resistance for a front
tire, but wasn't in stock today. (Another option, the Primo Comet,
which I have on my daily commuter Dahon Prestolite, was also in stock,
and would have been another good alternative to a Schwalbe Marathon.)
For the rear wheel, the fuller tread of the regular Marathon is an
advantage, especially in snow.