Tap to zoom in Opera Mini only zooms to one scale and back down again,. Essentially it is limited to only 2 views. Small and 100%. Safari can zoom right in and down in any increment you choose.
I think that's the thing we are forgetting. This isn't a fully fledged browser on a mobile device, as Safari is, it's a mobile optimised browser (hence the 'Mini'), with all the advantages (speed) and disadvantages that brings.
I notice that it seems to use it's own copy and paste functionality (which is also unusably broken). This doesn't seem like a finished product at all.
It is far better for some sites than Safari, when using 3G. Probably partly due to it lacking the ability to get bogged down by Adsense and other things which Safari tries to load. From that point of view, it's great to have around. It's not a Safari replacement yet though.