I currently have (2) Cat machines. A backhoe (416C) with over 12,000 hours, and an excavator (315C) with just under 5,000 hours. Both have been great machines and I still will lean towards Cat when I decide to replace any of the (5) machines I currently own. My experience wit hKomatsu is a rental WA200 loader (did not like it very much-the hydrostat trans) and running an employers PC200 back in the early 90s (machine was bought at auction and had about 3,000 hours-still a good trackhoe). That being said, Komatsu would also be in serious consideration. The downside of the Komatsu is that there is not a real dealership in my town (nearest is 3 hours away, different state and dealership than my region[dealer for my region is acutually 4 hours away] while Cat, Deere, and Case are in town). I have recently talked with a competitor who bought a new PC200 about (2) years ago. They bought it to replace a Deere 270. They feel as though the smaller 200 out performs the 270 in every way, including lift capacity. That's pretty impressive. So far they have had zero problems. This company has (4) full sized excavators. Another company in my area has 8+ excavators and loaders as well. They own Komatsu and Cat in various sizes ranging from 20 to 30 metric ton (200/320 to 300/330). The loaders are 938 to 950/ WA 320 to 380 size. Obviously this is a company that has direct experience, head to head, with both brands. While they do like the Cats the thing that stuck with me is that they said they just don't have to get parts or service for the Komatsus. It seems to mirror Steed's comments and it certainly is a compelling argument for Komatsu. I still believe that service is very important. The fact that, in my town, Cat has a full blown dealership, and that Komatsu has a service truck, a yard, and a double-wide trailer, further pushes me towards sticking with Cat.
For me, with my past experiences wit JCB backhoes, I would not be interested in owning a JCB excavator. Maybe if one was given to me but not if I had to pay for one. While JCB enjoys a lot of international success they continue to struggle to gain favor here in the US (IMO anyway). Lack of a good dealership network, past poor reliability issues, and the resultant poor resale value contribute to this. I'm not saying that you won't be happy with one. I suppose it's possible that a JCB could be the best machine you ever owned. My opinion on the brand will probably not change very soon. The only exposure I have, to the brand, anymore is at Con-Expo.
Back to the title of your thread:
If not Cat then who? I would have a hard time saying with 100% certainty (a lot of factors go into the decision) but Komatsu looks pretty good to me right now.