Firstly, whether a daily build is stable enough for daily usage mostly depends on your ability to troubleshoot problems. Secondly, the question was asked late April 2011, seven days before release day of Ubuntu 11.04. If you're seven days away from release day, if you have a working OS on your computer, I'd recommend waiting until release day. If you don't have a working OS on your computer, you're closer to release day than to the date the most recent alpha/beta was released, go for it.
What I recommend is to check the release schedule. If the feature freezes haven't kicked in yet, you could end up with very unpredictable results.
Another thing you can do is run the daily build as a virtual machine (virtualbox, vmware, etc.), and set it up as you normally would (extra repositories, run updates, etc.). Once you've tested it as a virtual machine and are confident that you can install it to your computer without trouble, go for it. Be warned, you may end up with irreversible problems where the easiest solution is to do a fresh install.
Lastly, as always, back everything up before you consider reformatting your OS partition.