Trigun is incredibly cartoony. It's easily more cartoony than Kenshin. But somehow, it doesn't seem to ruin the series as much. The series is a lot more light-hearted than Kenshin, which makes the cartoony bits easier to swallow.
The story is post-apocalyptic, sorta like Mad Max. Things look a lot more like the Wild West now than they ever did, but ancient, forgotten technology still dominates life. The plot concerns Vash, a silly ne'er-do-well who also happens to be an expert gunslinger, (Vash the Stampede, the "Humanoid Typhoon") who never kills. Unforunately for our hero, he's incredibly unlucky and everywhere he goes somehow ends up getting demolished. This, along with a strange event long past that Vash can't remember, has led to a sixty BILLION dollar bounty being placed on his head. That ain't chump change, even considering that inflation seems to be pretty serious, based on other stuff that's going on. The bounty means that a lot of people are after our hero, and it's usually these people who are the ones truly responsible for Vash's destructiveness.
Vash's constant property damage has another effect: he has two ladies who represent an insurance company following him wherever he goes. Meryl Stryfe, the one in charge and the one with all the common sense, is constantly amazed and ashamed of Vash. Millie, a total airhead who carries a gun that looks like a minigun but sadly isn't, is instead constantly amused by Vash's antics. Despite the lack of true minigun-age, these two still manage to defend themselves from the ruffians Vash attracts, while constantly trying to keep the damage he causes down to a minimum.
Trigun seems in many ways like the exact opposite of Kenshin. While Kenshin has every right to be a serious, dead cool show, Trigun has a much more silly premise and world, so the few bits of coolness that Vash manages are even cooler in comparison, just like those moments of stupidity in Kenshin ruin it so badly. In fact, Vash does actually sometimes approach almost Alucard-like levels of coolness, if only for a few seconds at a time. Unfortunately this doesn't stick, and even fight scenes can often be unbearably silly. Still, the silliness in Trigun is much more easily tolerated than in Kenshin, which makes Trigun superior in many ways. You shouldn't give up on Trigun after just a few episodes. Give Vash a chance to start being cool, which only comes later on. I have every reason to believe that past the point I'm at Vash only becomes cooler still. I'm looking forward to it!