a conversion wont have that "snappy" handling, if thats what you are looking for.
however, conversions can make great town bikes since the heavier tubes and slacker angles of old road frames are great for soaking up lumps in the road. proper tool for the job afterall...
i personally think conversions should only be done single speed (freewheel) because of pedal strike issues.
that bike looks to be in really good condition, so if it aint broke, dont fix it.
just ride it till (if) the shifters blow up, then think about single speeding it.