I always loved our front window, however...
That big sheet of glass is a weak point, for both impact and stress fractures along with leaking due to thermal expansion/contraction differences with the surrounding material. That expansion differential coupled with water being "pressurized" when traveling makes them leak prone, however, diligent inspection and repair of the caulking will take care of that problem. That is why most manufacturers no longer offer models with them. I, personally, lament the fact that they are getting scarce in bumper pulls and are non-existent in 5ers.
Personally, I would replace with tempered glass... Plexiglas, true, won't fracture (at least not as easily, it will, though, fracture), but, it tends to get cloudy with time and can be scratched. All Plexiglas windows I've had experience with have suffered from degradation after a couple of years; even "bullet proof" Lexan can be scratched. Glass, tempered, on the other hand, will stay clear (or tinted) for its lifetime and as long as it is installed in a "non stress" manner, should last for a long time. The trick is to get installed so that it is weather/water proof, without stressing/deforming the frame. If the glass is stressed, particularly with the extreme cold temperatures we've been having, it will break, even tempered glass.
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)