I love this series, actually. I always seem to like what I get when Yasuko Kobayashi is writing it, and this is no exception. Even before I knew she was the writer, this series jumped up into what WAS my top 3, turning it into my top 4 (if anyone's confused, it's not that I only like 3 other Sentai series besides Go-Busters. I'm just referring to all the ones that tie for first place in my personal rankings) in just a couple of episodes, and I can't wait to see just where this series goes.
I love Enter as a villain because he's actually competent, and even succeeds at times. Unlike with other villains where defeating the monster of the week and then the giant version was considered a "curses! foiled again!" moment, Enter runs it so that even if they beat the things, he still accomplishes a goal that furthers his cause, has the mindset of "yeah, the Go-Busters might win, but if they don't, then bonus!", and even despite being so much better at his job than many past villains, he also gives the impression he may not always care about the main goal because he's having too much fun just wrecking stuff up. I like competent enemies. I like crazy enemies. So I LOVE that Enter is both and keeps those two sides of himself balanced so effectively.
I like the Buster Machines, too, because they feel like regular Transformers combined with Transformers Beast Wars/Machines, Ace is a triple changer, which is always cool, and I just really love that there's a rabbit. I love rabbits. Go-Buster-Oh may not be too super dynamic in its fights, but it looks cool, and I have a tendency to forgive robots to a certain extent if their design is cool.
It's slowed down in recent episodes, but I like that they did henshins without using stock footage. Much as I enjoy a cool transformation sequence, seeing stock footage all the time eventually grows a bit old.
The good guys are fun, since we actually see the need for engineers and such for the giant robots, rather than just "we have a giant robot. it's always repaired the next time we have a battle. No, we won't explain whether or not it takes effort or just happens by magic." They even take time to show the other team members as actual people, rather than just set dressing. The main team is neat. I always enjoy seeing the Busters and their Buddyroids bounce off each other as they learn and grow, the boss isn't just some nice guy, which makes it fun to realize you have to root for a jerk, and the two assistants are entertaining in their own ways.
Lastly, I love the Metaroids and Megazords. The Megazords always look interesting in how they incorporate elements of the Metaroids into a pre-existing, mass produced design. The Metaroids are just plain awesome, taking simple objects (or a train) and turning them into a cool looking humanoid enemy (seriously, these are some of my favorite MotW designs in a while, particular examples as of the time I write this include Densharoid and Fanroid), and I always enjoy hearing the onomatopoeia, like Drillroid's whirring or Densharoid's "Ga-dan Ga-don".