Pros: Powerful, smooth operation, amazingly quiet compared to other trimmers
Cons: a bit heavy, harness doesn't fit well
We recently had the opportunity to purchase a new UMK431UNBA at a substantial discount from someone who had won it in a contest. The unit is a joy to use and I can't imagine that a better trimmer/brush cutter is available anywhere from any vendor.
I've used a Ryobi 890R (top of the line 4 cycle Ryobi brushcutter) for the past year and have put it to significant use. While I really like the Ryobi, and its engine has been very reliable, the construction of the Ryobi includes a substantial amount of plastic that is poorly bolted together and made of poor quality materials, so much so that the engine eventually broke off of the shaft.
To replace the Ryobi, we purchased the Honda with great expectations due to Honda's reputation. And I can honestly state that the Honda greatly exceeded our expectations and has been one of the best power tool investments that we've made. The unit starts immediately and easily, and the engine purrs smoothly throughout all operation. The engine (a 4 cycle) is *amazingly* quiet and there is power to spare. The u-shaped handlebars provide a significantly greater amount of control than the more-common loop handle, and overall the unit is a true joy to use for someone that has a significant amount of grass trimming or brush cutting to do. I smile when I use this unit!
On the down side, the unit is a bit heavier than most trimmers and therefore may not be as suitable for quick trimming tasks or small yards. To accommodate the weight, the unit includes a full harness that goes over both shoulders and around the waist, clipping together at a central location over the stomach. However, the trimmer itself clips onto the right side of the waist strap, and therefore places all the weight onto that strap. The result is that the weight isn't well distributed over the shoulders and instead mostly is born by the strap on your left waist side. After significant adjustment of the harness I was able to get my right shoulder to take some of the weight, but suffice it to say that the harness, while impressive looking, doesn't work so well on a trim guy like myself. In the end, however, it works well enough because the unit isn't really that heavy and I've used the trimmer for hours at a time without becoming fatigued.
In summary, I VERY HIGHLY recommend this Honda trimmer if you've got lots of trimming/brush cutting to do. It is one of the best constructed power tools I've every used, and the engine's smooth performance is truly amazing. The construction is very solid and the materials are of the highest quality (very little plastic). This has got to be the very best trimmer/brush cutter available from any vendor.