Thanks Gil, never had the Tamron 70-180, very briefly tried the 50-400 and wasn't impressed but I love the 28-75 G2. Very early days with the GM II, so far very impressed, so light for a large lens, today I was literally holding the body and lens with 2 fingers as I walked around, perfectly balanced. I almost went for the Tamron 35-150 but after reading a ton of feedback from owners I think there was a lot of initial hype around it, quite a few have sold up and gone with the GM II. 35-150 has no OSS, it's heavier, bulkier and doesn't balance on the body as well, seems very prone to flare and lots of reports of mediocre AF on moving subjects.