If you want the usual “look how great Mavericks is on the latest hardware!” kind of review, go to the big blog sites. I’m reviewing Mavericks or OS 10.9 on the kind of machine many users would — an older laptop, in this case a late 2010 13″ MacBook Air with 128gb SSD and 4gb RAM. It’s the kind of machine people might have rushed out to buy because it was the thinnest, lightest, and hippest laptop of the time. My wife bought me one because I liked my iPad so much, and I travel by motorcycle a lot, requiring a lightweight and small computer.

I heard OS X Mavericks was going to be free (at least yesterday) for download, so I backed up my data to an external drive and went for it. The download took 32 minutes on Comcast’s “Blast” internet (I’m pulling about 57-59Mb/s) for slightly more than 5gb. It took another 25 minutes for the OS to load and come up. Sign up is quick, but Mavericks forces you to create a new user profile for the computer — this caused some trouble as the new profile had all the admin privileges, so when I deleted it, I had to call Apple and have them help to repair my rights on the machine, as I could access the external drive. Your old profile will still be there, complete with all your files, settings, etc.

Now for the performance: Battery life is supposed to be much improved with the new OS. I did a couple of battery tests over the last day. The first showed a sharply reduced battery life, but I finally bothered to check and found it had been doing a 64gb backup through the first test, and was burning up the airwaves with the wifi transmitter. Even then, I got about 4 hours on the charge with moderate use. Today, I fired it up and did a usual work morning. Here’s how it looked.

Over two hours, with the screen at 40% brightness, bluetooth off,  wifi up and running a few tabs on Chrome, six Pages files open, mail up and running, the calculator, and notes open, Caffeine, a temp monitor and Sophos running in the background, I averaged about 4 minutes/1% of battery power, or a battery life of roughly seven hours. This is right about where the old Air was running under a similar load. The battery usage doubles if you have Flash intensive sites or iTunes streaming a movie, which is about what I was seeing with Mountain Lion.

So, no — you won’t get better battery life on an older machine, but you won’t see a measurable drop, either.

Heat and the screaming fans of doom was a feature that Mountain Lion brought to my Air. During the first battery test with the backup running, the internet seeing mild use, I was running between 150-190F, about 50F higher than usual. I would only see temps like this when I was ripping a CD or DVD under Mountain Lion. I was worried this would be the normal operating temperature (not good, and not just for the loud fan action.) The next day, after a rest, the Air was running at about 80/80F on the processors. I opened email and Chrome running up to five tabs, some with Flash. The temperature peaked at 169/175F with Daily Caller and other Flash intensive sites up and running. It dropped to 124/133F after a few minutes, once the Flash-enabled sites were closed. With the load mentioned for the battery test, the temp spiked at 117/129F and sat at 109/109F most of the time. So, Mavericks seems to run cooler for most tasks than Mountain Lion — but under any load, the heat spikes faster and seems to hold longer.

The last big thing is the memory management. Allegedly, the new OS compresses RAM use and makes it seem like you have about 50% more RAM than you do. I don’t tend to buy into this and remember software compression for memory that was out for Windows and worked about as well as a sieve to stay dry in the rain. This is unscientific, and totally anecdotal, but yes — I’m seeing more speed out of the Air. Boot time seems slower, as does shutdown — I would usually see about 20 seconds to boot up and 30 to close down; Mavericks is about a third slower coming up, and about the same shutting down.

I just tested a few apps I use regularly to see what I would get. iPhoto is a pig on the best of days — it opened and was usable in 5 seconds and shut down in about the same time; this is about 3x faster than it was. iTunes is similarly terrible about booting up — it came up in 5 seconds, but took 15 to connect to the external drive and bring everything up. It was laggy for another 10 seconds while it connected to my iPad. This is a good 3-4x faster than it was. Acrobat is a bit slow, but came up to a graphics heavy book in Acrobat in five seconds and closed immediately. Pages opened to a graphics heavy file in 3 seconds and closed immediately; Keynote was the slowest of the iWork suite at 7 seconds for a 20 slide presentation, and 5 seconds to close. Word took 26 seconds to open to a blank file — way to go, Microsoft! Thinking this might be related to the program being used the first time, I closed it (it closed immediately), I opened to a file. Three seconds. Fast enough to be well within my comfort zone.

So is Mavericks faster? Depends on the program or application, but it is noticeably faster.

There’s a bunch of additions to the OS — a maps program like iOS7 (won’t use it.) and improved Messages integration (but it’s still not syncing with messages received by the iPad and iPhone.) The notification center is mostly untouched, as are the gestures. iBooks is included (a nice touch and one I will use.)

Is OS X 10.9 Mavericks worth it? Yes. Even on an older machine, it seems to improve performance, without any real loss of battery life (nor an improvement on the late 2010 Air.) It will make your machine run hotter, but it seems to come in spikes, or whenever you are running Flash or video. Heavy wifi use seems to be tied to the heat. There’s a couple of new features that you might notice and a few your most likely won’t.

UPDATE: I’ve had a few days to play with the new OS X and I’m now more happy than I had been. I had a night out working for four hours with documents and a few images — in four hours I was at 71% battery, about a third better than I’d usually get. Not content to have one good cycle, I pulled the plug this morning at 1212 hours and spent the first hour streaming music from my external media drive, and bluetoothing it to an iHome speaker, while working on the internet and playing with Pages 5 (DISAPPOINTED!!!) and at this time, it’s been a bit over six hours with steady internet usage and writing and I’m at 38%. That’s roughly 10 hours of use out of a 2010 Air, or about a 25-30% increase in power.