I have been using Philips QT4011/15 Titanium blade Beard Trimmer since more than 2 years and this review will be a direct comparison of the Mi trimmer with Philips trimmer.
Build quality of Mi trimmer is much better with a solid body. The blades and screws on it give it a premium look. The small and large-sized combs which come along with the Mi timmer also sturdier-looking. Philips QT4011/15 gives only 1 comb which broke from one side on about 15-20 usages for me.
Features of both trimmers are similar. Mi trimmer has more length option at 40 compared to 20 for Philips. The dial on Mi trimmer is much easier to use. Mi trimmer has a USB cable for charging which makes it very convenient to charge compared to Philips which has a proprietary charger included in the box. A big advantage for MI trimmer is that it is washable which makes it very useful in the bathroom. I noticed that the combs are much harder to remove from Mi trimmer than the Philips model.
When the trimmer is turned on Mi trimmer makes very less noise whereas Philips trimmer is like a small motor running. I found hair trimming to be similar for both trimmers but I will update the review as I use it more often. As this is a new product I will be able to comment about the durability of the Mi Trimmer only after a few months.
Overall the Mi trimmer is cheaper and better in all the aspects. In trimming I found it to be similar to Philips. So it makes much better sense to buy Mi Trimmer than the Philips ones.