My vote for the easiest lightweight bag is the totally. You can't beat the zipper, and the side pockets are very nice to stick your cell phone in or keys in. I find it very lightweight which is not the case with all bags!! Easy in, good on the shoulder. If you have the chance go to the store and try on the different sizes. I have the MM and love it! It is perfect!!!!
I have the palermo pm and while I like the two ways to hold it, the actual shoulder strap is not comfy. So if you are a shoulder bag girl, I think there are better bags than the palermo. (the gm might be different, I have never tried it.)
The BH is another great bag. Very comfy on the shoulder, easy, casual, but no zipper. It holds the same as my totally mm but not as much room, I actually think it looks better if you carry less.
I tried the monty but didn't find it comfy, it sat weird under my armpit and felt funny.
I tried the stresa this weekend and it does fit nice on the shoulder. The straps were a little stiff but I am sure they would soften up with use. The strap on it leaves me a little worried, not as easy in and out. I have the bowling bag with the strap on it and you can put the strap in the back pocket out of the way when you want to get in the bag, but with the stresa you can't do that. I worry that it will fall back again the metal and make scratches.....not sure if this will happen but that is the one worry I had when I tried on the bag.
Overall, I like the totally or BH best. I have the totally in azur and want one in mono too!!!! Go in the clubhouse and look at all the fab totally pictures!