I have been using Philips QT 4000 trimmer for a long time now and I don’t have any complaints. Starting from battery backup, it servers for 3 full beard trimming and that is a really good one. It has quality blades that don’t leave any scar on the skin even when trimmed at zero.
I have got as much as 10 levels with its external extension attachment, so you can grow a loong beard and trim is as and when you want. Only slight disadvantage is charging time is pretty slow as it gets used. I won’t say this is a huge disadvantage because this is applicable for any electronic/electrical device. It is slightly costly compared to the local brands, but this is Philips and branded. So it is worth paying. Overall a really good trimmer and I recommend to buy it.