What is Paul telling his readers to do in Phil. 3.2?

In my Intermediate Greek II class we're translating Philippians; you can follow along (and even participate) over at my wiki, GreekBible. While we've been having a number of conversations (some more interesting than others), I haven't really thought to post very many of them here. This one, however, I'd like to solicit view points from a wider group. So here's my comments and my question about Phil. 3.2:

We won't get very far at all translating Philippians 3 if we don't get βλέπετε right. Sumney (2007: 70–71) renders the three-fold imperatives "Consider [x]" on the basis of syntactical evidence (viz., in every instance of the imperative βλέπετε with an accusative, it means "look at, consider"). O'Brien (1991: 353–354) insists that "the present context is urgent and, superficially at least, appears as a warning" (354, ftn 42) and so translates βλέπετε as "Beware of [x]."

I'm not so sure that Sumney's argument is very persuasive. Βλέπετε + acc. occurs, in the Pauline corpus, at 1 Cor. 1.26; 10.18 and 2 Cor. 10.7, in which the usage here supports his point. Even so, I'm not sure this evidence means that Paul cannot be using βλέπετε + acc. in the sense of "watch out for." And yet I agree with his conclusion, in part because I'm not sure the "urgency" O'Brien finds here at the beginning of chap. 3 is really there. Having just exhorted is readers, χαίρετε ἐν κυρίῳ, Paul may be holding up non-Christian Jews as an example of people who do not rejoice or who are otherwise not very popular in the regions surrounding Philippi (cf. Acts 16). In that case, the whole of Philippians 3 isn't a warning but a contrast.

This is why I think it's so important for us to consider how we render βλέπετε (pun intended): This will determine what we think is going on in the rest of the chapter. If "Beware of," then dark clouds have come over the otherwise encouraging and joyful epistle to the Philippians. if "Consider," then the encouraged and joyful Philippians are contrasted with figures whom Paul does not consider very joyful. The answer to this question, then, will depend in large part on how each reading jives with the rest of the chapter. So . . . which do you think fits better?