I installed Mavericks on 15" 2011 MacBook Pro with no apparent problems or issues.
The Download from App Store is large (5+ GB) so of course it takes a while (a couple of hours in my case). I took the computer up to the router and plugged into Ethernet rather than wireless.
I had of course done Time Machine and CCC backups prior to this process, and had also done a Disk Utility Verify on the HD.
Once the download was done, I created an install/recovery USB stick (an 8GB thumb drive is needed). Follow these instructions for an easy way of doing this (I used the Terminal command line version).
This takes 20 Min or so to do, but worth it. You can use the USB stick to install on other machines, and it's not linked to any Apple ID.
The actual Install and setup process can take a couple of hours or so. There is a quick first "install," then the real installation happens upon Restart. This is a two-step process. The first "install" took about 45 min., then another Restart, with a "Completing Installation" message with a 7 min estimated time. This was more like 20 minutes. Don't believe the "less than a Minute remaining" prompts on the progress bar. This "minute" is from some alien Einsteinian space/time. In reality, the last "minute" is more like 20-30, and you may think the process has stalled. Do not interrupt it, be patient, leave the room, and let it finish.
Upon launch of Mavericks, you will be prompted to deal with your iCloud setup, and also you must create a 4 digit PIN/Security number, and also asked to provide a phone number where an SMS (text) message may be sent if necessary.
Once the install and the Twenty Questions have been taken care of, I've found no anomalies or glitches (so far), and no negative change in UI speed or response. Battery life on the laptop is supposed to be improved; have not tested this yet.
Before updating, DO make sure you have any Safari Plugins or Extensions either updated or un-installed. Same for any third-party apps or tweaks to applications or system. Make sure your Applications and Utilities are good to go on the new OS.
An extensive, exhaustive 24 page review of Mavericks, by John Siracusa at Ars Technica, is well worth a read.