OPT vs H1b: change of status and consular processing

[echostate]

Hi all!

I'm an international student with F-1 visa. I'm graduating in May 2012, start working in July 2012, I already have my OPT applied to start work in July. Meanwhile, my company also want to file the H1b application for me this year (they said they don't want to delay to next year).

Now I have two options for the H1b application:
1) file H1b using "change of status", and in this case, I will use my OPT to start work in July 2012, and automatically transit to H1b in October 2012.
2) file H1b using "consular processing", and in this case, I can choose to use my OPT for about a year (July 2012 - June 2013), and activate H1b sometime before July 2013, by traveling back to my home country to see the US consulate there (aka "consular processing").

What I want to know: what are potential benefits for "consular processing" option (i.e., use OPT for about a year first and then switch to H1b)?
e.g., I heard that being in OPT status might save me some tax money ...
e.g., I heard that being in OPT status is good if my company fires me ...

*Most importantly*, is "using OPT as much as possible before transiting to H1b" good for getting the green card?
1) someone said yes, because I can use my OPT time to start applying green card, which will earn me extra time (in addition to whatever time period the H1b status can give me) before I get the green card.
2) someone said no, because delaying switching to H1b may also delay the time I get my green card.

I'm confused, I guess people have these two opposite options must be talking about different paths to get a green card?

Please advise, thanks!