Yes, it is that good!!
But you have already missed quite a lot! Unfortunately it might be a little difficult for you to follow all the plot intricacies at this point...
They've already repeated most episodes. I'm not sure if they'll repeat everything in order during the summer hiatus, but that may be your best bet.
That said, maybe you could tune in this week and see if it's worthwhile to jump into midstream (it'll be a repeat of an episode aired late last year).
"Lost" airs Wednesdays at 8 eastern/7central. Here's the official website:
http://abc.go.com/primetime/lost/
Thanks, maybe I'll catch the repeats this summer.