5.3 to 3.0 but worried about the oil leaks

[Jricharc]

So I have 19' 5.3 RST w/ 28k miles and I have been looking at ordering a 23' RST 2/ the 3.0. I just saw a 2020 RST exact same color as mine w/ the 3.0 but it has 42k miles, I have heard people having issues with the rear main seals leaking, my brother-in-law has a sierra 3.0 that has a small oil leak somewhere so I am hesitant now on these engines. Are they reliable and that much better than the 5.3? I have a travel trailer that is about 4,500lbs that I pull so I thought the 3.0 might be a better option for fuel economy but curious to hear real world experiences. 

[Nathan Hansen]

I have one absolutely love the truck, but I had to dread it oil leak finally got it dealt with and my transmission had a little chatter at 150,000 miles. I got them to warranty the transmission and why they had it out. They did my timing belt, cause it’s in the rear. My oil leak was coming from my valve cover. I think all data is 12 hours to tear everything down to get to it and then assemble it but now that they got all the leaks fixed or while it was a part day, silicone front and rear plugs that are known to leak. So far 2000 miles and good with a total of 153,000.