What makes you think they are troublesome? Personal experience? It's usually the balance shaft bearings that give in first, sometimes stripping the balance shaft gear. The pulley is on the balance shaft, and if the v-belt for the alternator, fan and water pump is overtightened the bearings have a hard life. I've never seen a cam gear strip, and the crank shaft gear is steel. You can get all metal timing gear sets, but I dread to imagine what happens if the front balance shaft bearing fails and the gear isn't the next weak link. In practice the fibre timing gears are pretty robust, in most V4s I break they're in perfectly fine condition and measure within spec.
In my experience the Cologne V4's weakest point is the PCV system. Apparently not many people seem to notice or understand this and completely neglect it, and I've seen many V4s that died as a result of black sludge.
Fair to say the V4 and V6 Essex seem to suffer failures in different ways - timing gear failure is becoming quite common and there have been some instances of it happening on the Cologne V6 (in 2.8 guise).
Anyway - this thread's about the Taunus/Cologne lump I think the Saab is the only car sold mainstream in the UK which had it fitted? All the Ford vehicles used the Essex V4 IIRC?