I'm in a current dilemma of deciding which tamaogtchi to get as well! Although, i have decided that i will go for the colour ones no matter what. I'd played with the older b/w ones before. They are fun, but since i haven't been playing it for a long time, and this time i want to go a long time playing, i decided i want the colour because it's such a big jump from before.
Also, about learning the Japanese, i'm currently studying Certificate 3 for Japanese, but my Japanese is terrible. I remember navigating a tamagotchi that was in japanese when i was 7 years old. If i could handle it then and not know what it was talking about, now that i'm 20something, i'm sure it can't hurt (yes, i am old. T_T).
With a lot of the youtube videos i've seen so far, it appears that the JApanese isn't really too hard to decipher, as a lot of it is in Katakana. If you just read that phonetically, it's actually almost the same as english!
But if not, when i was a kid, i just kept pressing stuff until my tamagotchi was happy~, so, i don't think it'll be a big difference this time...
But there's my 2 cents.
p.s if i wasn't so hell bent on getting a colour, i was gonna get the 3 tamatown ones from amazon that added to $50 all together. I wanted more than one, so the tamagotchis can interact with each other. So it does depend on what you really want out of it. I want the cute stuff, the colour, the melt-your-heart cute animations, thus i wanted the colour ones.
GOOD LUCK WITH YOUR CHOICE!