I can give a comparison! I sold my 96 XR4 for an 06 WR.
The pros. e-start, oodles of power, fantastic suspension and handling.
The cons. Rock hard seat, more maintenance.
That about sums it!
Although I wear padded shorts that make the seat bearable and the maintenance is really not that bad. Oil every 1000kms, and that is what I did on the XR4 anyway.
If you are doing long days of trail riding and nothing too gnarly then the XR is probably better. If you are getting into some more technical areas then the WR takes over as it is lighter and a lot easier to wrangle around tight sections.
Oh and the power! It is very different to the XR. Not as much of a torque monster but it has enough power to really get you into trouble if you are not concentrating. The WR is not very forgivable compared to the XR
So is one bike better? No. If you love your XR and have no issues with it, then keep it. If you are finding that you have modded the suspension and handling as much as you can and you are still not satisfied and you want some more power, then get a WR.
Sent with a leaf using a pointy stick.