I have used the battery-operated Panasonic models, and the single-handed manual
ones. But the Groom Mate Platinum XL is my favorite.  It takes a little effort to get used to the two-handed operation (hold the trimmer in place with one hand, twist the base back and forth to activate the rotary cutting blades), but once mastered, the cutting blades work really well, the small size makes it great for travel, and never needing to buy, recharge or replace batteries is a plus, and it's guaranteed for life. Buy it for $19.88 at Amazon.com.