First of all, I in no way intend to insult those who think Lion is the greatest iteration of Apple's generally superb and rock-solid OS'es. This is simply my view and experience using it. My system is a mid-2009 13" MB Pro, 2.26 Ghz C2D, 4 GB RAM. I've been using Lion from 10.7 to 10.7.3 (even before it came out officially). The good things about Lion: 1 - iCloud. It just works, and iMessages (beta) is a very nice addition. 2 - Full screen apps, in a way it's nice to have Safari or Reeder take up the whole screen, especially on my 13" MB Pro. 3 - Finder. It's much, much better. The sorting features are a given. 4 - Native scrolling. I love it after I got used to it. Just feels awkward using it with a mouse. But the rest of the gestures are really nice. ....that's it, really. The bad (the 'oh boy, where do I start' section): 1 - TERRIBLE RAM management. I have never seen such a bad OS when it comes to this. Even Windows Vista was better managing memory on my old AMD Athlon 3200+ with 1 GB RAM. To prove it, over the last five hours, I ran a Windows XP VM with some light programs. On the Mac side: Photoshop, Firefox, Adium, Echofon, iTunes, Mail, etc...nothing REALLY that heavy (and my PS usage was really to open 3 or 4 images and edit some hue/saturation). Lo and behold, this is how my system has been brutalized (I have closed PS and the VM while taking this screenshot): The pageouts are unacceptable. My OS runs okay with the basic apps. If Photoshop is idle and my Win XP 512 MB RAM vm opens a bunch of apps, there goes my fluidity. One thing: Echofon. I'm an avid Twitter user, and I love that client. On Snow Leopard, with the latest version, it never locked up. Not one beachball. Zero. Nada. With Lion? Okay, you boot it up, if you're lucky enough to not get a beachball while it's loading the timeline, you're blessed. If not, you have to wait 2+ minutes for it to load. After 15 minutes, between switching apps and checking my timeline, it starts to beachball and slows to an utter crawl. Even if it's the only app running with around 2 GB free RAM, it still is very, very badly optimized for Lion. This is the one app I love to have in the background, and now I can't even do that because if I need to use it for some reason, it locks up randomly. Terrible. And don't tell me to upgrade to 8 GB, the SAME system under Snow Leopard very rarely locked up (and I'm talking about twice a month, more or less, 'cos I never turn my Mac off unless I have to upgrade). Now, beachballs are a constant. Every single day, multiple times. I refuse to spend more money to make my system work decently again when the latest beta (yes, beta) of Windows 8 runs better on my system than any Apple OS ever has. And now you're thinking - oh here we have a Windows fan. No, I just use Windows for gaming. I'm merely stating that with the same specs, one OS runs a lot better than the other. 2 - Mission Control. It kills my productivity. I used to have certain apps assigned to certain spaces, all neat. Now, that part still works, BUT App Exposé is terrible. I want my Exposé to show like in Snow Leopard. Don't show me all windows for the current app. I could do that by clicking the dock app icon! Seriously?! Most apps don't even CREATE multiple windows (like Firefox, everything is in tabs). I have to resort to use the Dock to change apps decently, and that still requires that I find the window I want if, for example, it happens to be Finder. UGH. 3 - Launchpad. The most useless piece of crap ever made. The most use it got was straight off my Dock after I fiddled with it for around 10 minutes. I know that Mountain Lion has added a search bar (hurray!). Basically, it's terrible. There is no decent ordering, it dumps all my apps in there just like that. If you want an iPad, get an iPad (and it just works there). But if you're gonna port things over, at least make them work correctly, Apple. Alfred/Quicksilver do what Launchpad does with half the effort and a fraction of the time spend looking for the correct app you want to open (and much, much more). 4 - Resume. Kill.me.now. I still cannot get over the nightmare I had the first time I shut down my Mac, with 15+ apps running, only to have them ALL boot up at startup....and the checkbox doesn't remember your pick! You can't even launch 15 apps at the same time unless you have an SSD (unless you wish to wait for 10 minutes). My computer lags on Lion if you try and open FF and iTunes at the same time. It's such a stupid feature. And App Resume is just as pointless. I mean, why would you resume Preview, for example? Imagine if someone was looking at something they shouldn't have (just saying), and then their teacher/mom/whoever opened Preview for some reason.....seriously. The worst that happened to me was when I wanted to open two images to compare side by side after a photoshop edit, and then it opened up all my work .pdfs. I had to go and close them one by one. How enjoyable. 5 - Presentation support...I loved how Snow Leopard worked with multiple monitors. Now, if you try and show a full-screen app, the other desktop just gets a grey backdrop. It's so, so broken I couldn't even fathom how to make it work again. 6 - Minor things like clicking on the trackpad to wake up the Mac...before it worked with a simple tap. Spotty wifi. And the 'save as' feature. Don't even get me started on that one... Final Summary: Basically, Lion is a let-down. For me, at the very least. I feel I'm less productive with all the time spent changing desktops, finding the right app, not to mention the terrible memory management. And don't tell me to get freememory pro or whatever. The system should do the memory management for you without having to purge it manually. If you're using apps like that, it just shows that they really messed things up in that department. Like one reviewer once said a few months ago: "OS X is like a beautiful girl, and every iteration was a new outfit. Snow Leopard was sort of a cheerleader outfit. Now, it's like they shoved that cheerleader into a pile of crap and called her 'Lion'." The 'cheerleader in crap' analogy just comes to show how much is bad about Lion. I'm not going to quit Apple just because they messed up an elementary feature like RAM management. No, I love Apple and they make great products. I will just wait until they fix this mess of an OS (possibly with Mountain Lion - I tried it out a while ago and it seemed a lot more fluid) and then upgrade. For now, I'm going back to SL as soon as I can find that installation disc. I'll miss iCloud and iMessages, but as long as I can get the mail to work with it. I can still use my iPhone, so that's not a major issue. I hope that those reading this can relate to at least one of the problems above. I feel your pain. For the rest that never had any problems with Lion, well, I'm happy for you.