非常感谢8老师的回答！这样看来其实L1B只有在17年和18年抽中H1B才有优势。如果17和18年H1B抽签不中，如果我被裁，我就得回中国，因为我也不能再用前一个H1B。如果19年抽中H1B ， 只有3年的期限，和140批准后3年延期是一样的。
如果20年和21年抽中，还不如140批准后的3年延期。所以我还不如用前一个H1B，然后希望140能尽快批，这样我的H1B就可以3年3年延期。请教8老师，我的逻辑对吗？
--Right. If your employer filed PERM now (before you enter US) or immediately after you enter US using H-1B visa (Choice 1 as you as you mentined), then you can extend your H-1B beyond the 6-year limit using the PERM one year later after the PERM filing or any time within one year plus 10 months after the I-140 approved. Then, you can extend the H-1B again and again until you file I-485 or get the green card.
By the way, PERM and I-140 filing can be done any time and you don't need to be physically present in US. So, ask the employer to do it now (the sooner, the better). After the PERM is approved, the employer can use premium processing to get the I-140 approved in 15 days, thus you can extend your H-1B for another 3 years at one time using the approved I-140.
After you extend your H-1B beyond the 6 year limit, you can transfer H-1 to a new employer using the approved I-140 and extend it again and again as long as your current employer does not request USCIS to revoke the approved I-140.
