Will Google position the URLs with same page rank in both cases?
Which is fast and good?
Will all URLs in the site map get indexed?
You have included few things in the question, the following should clarify.
XML Sitemap: When you submit XML sitemap, Google algorithm reviews it and it will index pages based on its algorithm. There is no guarantee that it will index all submitted URLs.
XML Sitemap Priority: It only lets the search engines know which pages you want for the crawlers understand in terms of priority. The priority you assign doesn't influence ranking.
Re-Indexing: Google algorithm re-crawls pages in certain interval regardless you submit xml sitemap or not.
How to get crawled fast: There are several factors you can consider like:
- Have HTML sitemap, still very handy search engines.
- Do internal linking from important pages based on your priority.
- Submit XML sitemap
- Share pages on social media sites, G+ is an important to place to start.
- Build authority in general which can also influence fast crawling.