Even though you say small is 15-30W, the 3 you mention are all in the 15-watt range. That tells me you're budget is $100-$150. Not sure what your needs are -- practice or gig-worthy:whatever:
If it's practice at-home, 15W will do. I'm not familiar with those 3, although I had a smaller (10W) Ibanez Troubador briefly (it was OK, I guess) but I've noodled on one of these at my local store, and I think fellow fretter luvmyshiner has one:
Behringer Ultraacoustic 108
Behringer is poo-pooed as crapola by many gearsnobs, but for decent clone gear at budget-conscious prices, or for those just getting started, much of their stuff is hard to beat. That thing is only $70...If you hang with it, and save on the side, you can always upgrade later.
But if you want to play out, you need at least 30W. Minimum. Again, this Behringer is decent, and under $200. Still, just an 8" speaker, but more power and frills:
Behringer Ultracoustic ACX450
What's the best 30-watt acoustic amp, though? Might be this Fender, but it will break your budget:
Fender Acoustonic 30 DSP