As a fan of the genre, I feel almost offended by this show. To clarify, I haven't seen the original series (or movie) either, so I have no nostalgia goggles to shatter.
I thought it started out alright, but the further it went, the more wrong it got. First of all, the lead character. I'm happy that we have a leading lady doing her own stunts, but she can't act all that well outside of trying to be a bad ass. Shane West isn't much better, with his one facial expression and tone of voice. In fact, everyone on this show, sans Birkhoff, act like they have a stick up their ass... which is not that fun to watch. Although, Lyndsy is at least trying to deviate. I give the writers credit for at least trying to spice things up. It just fails horribly.
After Michael joined Nikita as a second mole, things just started spiraling. I didn't even know that it was possible to make the two even more unappealing. At least prior to that they had the rivalry thing going. And then the "reveal" of Nikita killing Alex's father made me feel like the writers think we're stupid and have the attention span of a goldfish. Anyone with a working braincell can do the math and come to that conclusion. In fact, it makes Alex just look like an idiot for not coming to that conclusion herself. Don't even get me started on the season one finale, where I was one step ahead of them for the entire hour. And the shot of Michael and Nikita driving off into the storm was just hilarious.
In closing, if you want to check out a show about assassins and a morally ambiguous secret agency with a female lead, don't go for this show. Instead, try out Dark Angel, Dollhouse or even the eight episode Bionic Woman remake first.