I have a 2010 MacBook Pro which came with a 120GB SSD. I ran out of space on the drive and took it upon myself to upgrade to a bigger one. Found a great deal ($220) on this SanDisk Extreme 240GB 2.5" SATA III SSD and was ready to swap it out with the old drive. It turns out I'd lost out on the lottery and received one of the slower Toshiba SSDs rather than one of the faster Samsung ones, so I knew the SanDisk was bound to be an improvement. After making sure my Time Machine backup was up to date I cloned my old SSD to the new one using a SATA-to-USB dock and Carbon Copy Cloner.
I started by watching this video to get a sense of my way around the inside of the laptop. The video covers a slightly different task, but I wasn't looking for hand-holding, but just the general layout and gotchas. One of the things I gathered is that it's important to use high-quality philips and torx bits, and in my case I used a Wiha set. It was pretty easy to take out the old SSD and plug in the new one. I couldn't find my anti-static wristband, but I made sure to wear only cotton clothing, and to touch the power supply chasis of a nearby, plugged-in desktop PC every minute or so to avoid zapping anything.
With the new SSD in place, the first boot took an eternity. Almost ten seconds from pushing the power button to the grey Apple icon, and almost another ten seconds before the little spinny boot process indicator, but it did boot up fine. I've heard that SSDs need a few days to "settle in" before they're at proper performance levels, but other than the super-slow boot-up , I haven't had any other problems. I was back to working normally right away with the new SSD. Using Blackmagic Disk Speed Test I get speeds of around 220MB/s for read and 260MB/s for write, which is quite an improvement (and this is before any possible "settling.")