In the past, if the company laid off you, the company needs to pay you air ticket for you to return your hometown. In order to avoid this, some companies like to keep you 2 months without pay. During 2 months, you are still valid H1B. If you can find a new job, the new employer sponsors you H1B transfer. Basically, the company gives you two months buffer.
I am not sure if it is rule or it is various from company to company.
My understanding is H1B transfer is better. If you apply new H1B, I am not sure if you need new H1B quota. If new quota is needed, the new H1B quota is only available in Oct 2008. And USCIS only accepts new H1B application starting Apr 2008.