Another Ryobi user. Started with a drill, then a hedge trimmer and recently I bought a second hand lot from a tradie who had flogged them and then upgraded so I've got a kit of around 15 tools. A couple of the second hand bits were dead, but for amount I've paid I've got nothing to lose with them.
Don't worry about the biggest battery for a drill, I've got 2x 1.4ah and 2x 4ah. The smaller batteries are great for the drill, nice and light, no loss of power and run time is plenty. The bigger batteries make a difference on high speed stuff like the circ saw or blower. Having two smaller batteries for a drill is good, always keep one charged in case.
The other thing I did was when I bought my Ryobi drill I had some old GMC 18v gear that had dud ni-cad batteries. I bought the cheapest Ryobi skin I could find (torch) cut the base off it, grafted it to the gmc battery shell once the batteries were removed. Now it's possible to use the old gmc drill, jigsaw, recip saw with a Ryobi lithium battery. The battery/skin system does lock you in a bit, but not completely.