Well... I consider them a guilty pleasure. I played SW3, and honestly, it was total crap. The controls were choppy, the graphics sucked, the AI was horrid. It SHOULD be awful, but I found it actually amusing. I couldn't stop playing it until my Wii broke. I would rent another in the series before buying one.
Also, I've heard good things about the Dynasty Warriors series, which is almost the same thing. I'd try checking that one out first.
I've played the 3DS (pilot wings) but did not get a chance to play SW's yet. The controlls on the 3DS are very smooth and accurate. The 3d affect will look great with SW though it takes a few moments to adjust everything and get it right. From thouse I have heard who have played it though on the 3DS it is worth it.
Samurai Warriors has no cheats. The only thing you'd need help on the internet for is finding which stages are needed to get the bloody bonus weapons. After that, it'll just be you yelling for 3 hours trying to get the 5 Star missions to appear for the 18th freaking time.