Expand the ‘Notebooks’ section to reveal all the notebook stacks and notebooks not organized into a stack.
There are too many "missing" features to mention when comparing the (new) web client and Desktop. but if you like the new web interface, it might just be your zen-like environment in which to work if you're writing, for example.
For sure, you'll find more versatility on Desktop. If you were restricting your experience to the new Web Beta, I'd say you might be missing out on a number of Desktop features. you may very well end up using both on a regular basis. I'd tinker around with both Web and Desktop if I were you. and at other times I prefer the feel of the desktop. For some things I prefer the feel of doing something on iPhone/ iPad. and I've found that it's not only a matter of practicality or available features (using the device that is available/ within arm's-reach).
I personally use iOS and Windows desktop clients. although, I think it quite interesting to become adept at switching between clients comfortably. You'll find the desktop client much richer in terms of features that you can tinker around with. but, then again, as you mentioned, you're somewhat new to Evernote and may not have that many notebooks to search anyways. As it stands, you'll find it difficult to search through notebooks (web client). It might be just up your alley if you want to create a note right off the bat and have a more distraction-free experience - or at least that is the intention. Many people find the new web version to be very basic and rudimentary. If you've recently moved over to the new Web Beta, you'll have noticed a wildly different user experience (to desktop). Thanks in advance for the help and again, sorry if I come across as a complete tool. the online version? I mean I understand it's safer to back up my stuff to my desktop and the cloud but are there other advantages I'm missing?