Joe,
The par fives at Tullymore have more tree trouble than the three Colorado courses I've seen (Lakota, Redlands, Pradera), with #8 having the "tree-gate" of sorts and #18 also having a couple that challenge going for the green. There's a fair bit of water on the ones at Tullymore too.
The sand and water are fairly evident in Colorado as well, with not as much water as Tullymore (mainly because Tullymore appeared to built of of a swamp somewhat...so there's a lot of water to be found). Lakota has a fair amount of water, but less so at Pradera and Redlands. There are smaller trees present occasionally, but nothing like Tullymore.
I really like the use of the trees to dictate angles at Tullymore. Especially on #18 it forces you to take a brave line to give yourself a real chance to get home in two. Two well-placed shots leave a clear 3rd, however. The water really creates heroic opportunities as well. They're usually very daring and very fun.
If I had to pick a negative there is some repetitiveness to them, especially once you've seen a few Engh courses. I'm not sure I couldn't say something in that regard about just about any architect, but Engh's style is dramatic and unique, so it stands out more with him. Plus I tend to like his templates and hole styles, so I enjoy seeing them on different pieces of ground.
They often tend to be downhill. The 5th at Lakota is 600+ yards and I hit the green in two with an iron. Same with #16 at Pradera. Those are the only two times I've ever hit two shots that far with any two clubs