I have a pair of Macbooks-a late 2007 model in black, and a white mid-2009.
Both have(cheap) SSDs-a 120gb Sandisk in the black Macbook and a 240gb Kingston in the White Macbook. The Blackbook has 2gb of RAM and is running 10.7. It will very shortly be upgraded to 4gb-a friend has promised me some 2gb DDR2 SO-DIMMS from an old Compaq he junked. 10.7 is the maximum it will support. The white is running Yosemite(officially supported on this model) and has 4gb of RAM. It will officially hold 8gb, but IMO 4gb DDR-2 modules are prohibitively expensive considering the age/value of the computer.
I regularly let others use these computers, and everyone is impressed with how responsive and useable they are given their age. Both have Office 2011, Photoshop CS6, and quite a few other "heavy" programs installed-they handle them fairly gracefully, and of course with an SSD launch any of these almost instantly.
The Blackbook has its original battery with ~150 cycles on it and will reliably run for 2.5-3h on a charge. The white book had an a new aftermarket battery in it when I bought it that gave me no end of trouble. The computer would randomly shut off when running on the battery, and finally after a few months(and no more than a couple dozen cycles) got to where it wouldn't charge at all. Rather than buying a new battery from Apple(still available, but almost as much as I paid for the computer) or another questionable aftermarket battery, I gambled on a lightly used(reportedly 6 cycles) Apple OEM battery for $50 on Ebay. That battery actually is older than the computer(late 2008 manufacture date) but most of the battery utilities report it with better than 100% health and it will run the computer for a solid 4 hours.
After several bad experience with aftermarket batteries having very short use lived before they failed(primarily with PPC laptops, but also Intel), I've sworn off most of them. I stick to Apple OEM batteries, or if I must buy aftermarket I always try to get Newertech NuPower batteries(these are available from OWC). They are a lot pricier than most of the aftermarket batteries you find on Ebay, but are less expensive than OEM. In my experience they will power the computer for about as long as an OEM battery, last about as long as an Apple battery(~300 cycles), and tend to have fairly good fit and finish so they don't stick out like a sore thumb when installed. For older computers, they also have the advantage of likely being "fresher" than an OEM battery.