Absolutely it does. The modernisation is consistent and high-quality, with space used intelligently to get the most out of the usable areas of what is actually not a very big site. The zoo feels Imperial Austrian and yet also modern European. There are one or two exhibits (as always) that could do with a little tweak - I was pleased to see a (vaguely-timescaled, admittedly) plan to expand the giraffe paddock, whilst retaining its traditional Rotunda presence. But overall it's an incredibly good zoo, with a very well-balanced collection; a nearly-complete collection of crowd-pleasers alongside a very choice selection of obscurities (the amphibians in particular are a treat).
It's a comfortable top 10 zoo for me and a strong contender for top 5. A wonderful place - and somewhere certain other zoos (mentioning no Londons) would do well to pay attention to when it comes to modern exhibits in historic buildings on relatively small city parkland sites.
And to sit in the Kaiserpavilion eating one's lunch and sipping a cold Ottakringer whilst looking out onto exhibits constructed over 250 years ago (the pavilion was added to the already-constructed rotunda in 1759) and often still holding the same or comparable species, and doing it well, is one of Europe's great zoo joys, I'd say.
@Maguari: thanks for the great mini-review. Often zoo nerds talk about the historic aspect of the zoo (being of course over 260 years old!) but there has been a massive overhaul and modernization of Vienna Zoo since 1991. Apparently ever since Helmut Pechlaner began his tenure as director the zoo has radically changed for the better, and in his first decade annual attendance went from 700,000 to 1.7 million. That is an incredible statistic and there is a long list of projects that were completed during that time period. Now the zoo never dips below 2 million annual visitors but the modernization era has surely been the #1 reason for its success. Recent director Dagmar Schratter has continued changing the zoo for the better and it is now one of the best facilities in the world. If you build it then they will come...
One interesting thing we noted was roadside advertising for this zoo in Bratislava - on the one hand not that surprising as they're only 50km or so apart but for a capital city zoo to be being advertised in another country's capital must be something of a unique situation! Certainly it crossed my mind to wonder if the presence of Vienna just a short journey away might affect Bratislava Zoo's visitor numbers.