I have been trying most of the guitars in the market and may know a little bit.
I love to strum and sing too. Playing with a band means your guitar tone must cut through the mix. Usually strummers will go for dreadnoughts cuz it can handle heavy strumming. Some try to get a clearer tone with grand auditoriums and other smaller bodies guitars like OMs at the expense of bass, but that is not a problem if you plug in and EQ.
Choice of tonewoods is up to individual preferences. Spruce tops are the favourites - comes in Sitka and Engelmann. Sitka is bright and snappy, while engelmann is warmer and resonating. Favourite sides/backs are mahogany and rosewood. Mahogany has a deeper and dark tone while rosewood has more bass response and warmth. Know your favourite tonewood combination and you can easily size down your options.
For $400, you can get the Zion 21D - dreadnought. All solids tonewoods; solid spruce top and rosewood sides/back. Only thing is the Shadow piezo pickup sucks - quacky and sounds nothing like the natural acoustic at all. Available at Living Strings. Might have to replace with electronics in the long run.
The Takamines from Korea go about $400-$500 with pickups - some with onboard tuners. They can sound both bright and warm at the same time - they are quite similar to Martins. Not impressed with their electronice but they are good value for money. Available at Davis Guitar and Luther.
Then there is the Taylor Big Baby. A 3/4 dreadnought with solid spruce top and laminate sides/back. Sounds bright like most Taylors but its definitely not as bassy as a full dreadnought. Has that thin fast neck that made Taylor famous - electric guitarists love this feature. All the quality workmanship which comes with the brand. No electronics but that's not an issue for me. Personally, I like the option of installing my preferred electronics like LR Baggs or Bband separately. It goes for about $470 in the second hand market.
Another one you can consider is Art & Lutherie 3/4 dreadnought from Ranking Sports. Comes in black and sunburst at $350 new. Goes about $280 in the second hand market. Cedar top makes it bright and warm. Good workmanship from the parent company Godin. Canadian tonewoods in satin finish makes it very resonating. Only potential problem that it might not be made for the local weather - neck may warp. Other than that, its comfortable to play and has a great tone for that price.
If you are installing your own pickup, the most value for money is the LR Baggs Element Active at $188, add $40 for installation. Sometimes, you can get this in the second hand market for as low as $130. Single source UST pickup but good enough. No intrusive barndoor preamps; the only holes drilled are the endpin plug and bridge. If you need more fullness of amplication, place a second mic in front of the guitar to act a s a dual source.
Don't go for Ovation unless you play plugged all the time. Some can't get used to the bowl back shape and have problems keeping it stablised on their laps. So far, I'm not impressed with other brands like Cort, Ibanez, Epiphone, Blast in your budget category. Maestro is decent but you wouldn't want it after trying out their much more expensive Blueridge guitars.
Hope this helps.