I have a full jessem set up, can't recommend it highly enough for its accuracy and ease of use. I have DW625 2kw drive unit that does what its told without complaint. I also have a kity spindle moulder that will take up to 50mm knives.
Both are used for different things. I use the router more than the moulder, it's much safer to use. Moulders are dangerous pieces of kit, ( as is everything in the workshop, just that the moulder is more so!!!) and for small detail the router with the jessem set up is EXTREMELY quick to use. (rout-r-lift)
The finish on moulders is superior to that on routers, and you can achieve in one pass what may take many passes on a router. I only take cuts upto 5mm on the router, depending on wood, height of cut etc etc.
If you are doing lots of architectural detailing, then there is a huge amount on offer for a moulder. It really depends upon what you are going to use it for.Making windows or doors for commercial ends( moulder), or making a jewellrey box for the lady of the house (router).
Hoping to re gear the moulder would be difficult. Remember large router bits need to move at around 12-14k, smaller bits upwards and over 20k. (depends upon diameter and weight of the bits. ALWAYS check the manufacturers recommendation!!!)
Hope that is of some use.
Decklan