They're both good engines but I'm guessing this is your first engine swap, so I would stick with an LS. You can buy a complete swap with all the parts you need and bolt it and be ready to go (assuming you buy the right swap). If you buy a B20, you'll most likely be buying just a long block and pieceing everything else together (transmission, shift linkage, axles for one, manifolds, distributor, injectors, sensors if nessicary). If your unfamiliar with doing swaps and know what's supposed to be there in order to purchase the correct parts, you can get yourself into trouble.

There's been a debate on if the B20 sleeves are stronger or weaker than standard B-series but I tend to believe that if Honda had better sleeves, they'd use them in their Type R's and not the engine that goes in the CRV so there is that. Regardless, if you install a turbo and are too aggressive with the boost or have insufficent fuel, the stock rods are probably going to fail before the sleeves do (well, about .0025 seconds before, as the rods tend to travel through the sleeves when they fail). Personally, I would stick with the B18B and save up, do the swap first and see how happy you are with the power level. I know 14 seconds doesn't sound that impressive on the internet but B18C1 hatch ran 14.4 all day and was a blast to drive.