JOSHEWAH  I like this app a lot. I wish that flash and audio/video wouldn't reload every time I switched tabs though. If I am checking out a song from a blog in a tab and go back to read feeds while it plays it cuts it off and starts downloading again when I go back to it.  
(Version 2.2.2.2211b)

IVANOVITCH  A timely update: it was unusable with Remote Buddy open at the same time (made Vienna uncontrollable, oddly). Further, the display bugs introduced with Leopard now appear to be ironed out. No more truncated scrollbars or icons.

What's missing:

Still no icon to indicate that a headline has been opened in external browser: only option is to display read/unread and to manually flag item.

Also difficult to re-sort headlines by date (up or down) without doubling size of pane used for headlines (I use condensed layout to emulate previously purchased RSS readers).

Apart from this, it works remarkably well, and the price is brilliant value. Like others, I bought other readers but grew disappointed with the direction of development and features. I'm now happily stuck with Vienna.  
(Version 2.2.1.2210)

TINGTING  Needs more toolbar button options like "mark all read" "refresh" just a single feed. And not a drop down menu like it has where you get carpal tunnel click-scroll-click. One click. otherwise cool, I hope it grows in the right direction.  
(Version 2.2.0)

SCREENSHOT  I just started to use Vienna and the functionalities are quite ok. But could someone explain to me why Vienna connects to sites such as imrworldwide.com, doubleclick.net, metrics.apple.com, webtrendslive.com, tacoda.net, revsci.net and others?

I don't remember adding any feeds from those guys.  
(Version 2.2.0)

ZX81  I hate Vienna!

I bought NetNewsWire and Newsfire and discovered Vienna afterwards!!! Now I don't use the readers I have bought anymore and I've swithched to the free one...It's fast, easy to configure and use, can import and export my list of suscriptions (I exported it to OmniOutliner). The builtin browser is just great and seems to be able to open any Web page and download files (which isn't the case of NetNewsWire ; I've tested quite a few pages).

Very stable. Great app.  
(Version 2.2.0)

GATTON  I don't have a lot of experience with other feed readers but Vienna works very well for me. As a matter of fact I consider it a plus that I was able to set it up and begin using it so quickly having no experience with other standalone readers. The only other thing I have used is Google Reader. I'm very pleased with Vienna's features and performance. Worth a download for sure.  
(Version 2.2.0.2209)

PMANNA  While it looks it gets better, it still lacks the only feature that keeps me from switching, i.e. the possibility to subscribe multiple times to the same feed with different user names. That's the way some popular feeds work (GMail, for example), and it's supported in other readers.  
(Version 2.2.0.2207)

GAOSHAN  This has come so far from the first version I used (probably a year or more ago). I have always used Safari's built-in RSS feed reader but one day with Vienna and I switched.

Probably my favorite thing about it (and the reason I like it better than other free, standout RSS readers, such as NetNewsWire Lite) is the built-in browser for viewing articles. There is a basic web browser with back, forward, refresh and since it is based on webkit it functions and feels very much like a stripped down Safari.

Additionally you can send a link to Safari for viewing, if you like. Another thing that beats Safari's RSS reader is the ability to check individual feeds for updates rather than the whole collection.

There are also a number of built-in css styles that you can apply to your feeds, you can flag articles, use smart folders, etc. All of this for free! What a great product!  
(Version 2.1.1.2109)

HENRIKTEKNIK  Feature request:

Sorting feeds in folders, for easy cathegorizing. Also, maybe some kind of system menu bar access?  
(Version 2.1.1.2109)

TIMSTRINGER  I've been using Vienna to manage about 50 RSS feeds. I'm very impressed with the application, though I was finding that it was getting slower and slower to the point where it was almost unusable (e.g. it would sometimes take about 10 seconds for a news item to show up on my MacBook Pro).

The solution: I simply empied the Trash by selecting "Empty Trash" from the Vienna menu. From what I've read, this causes some sort of a compaction of the database to be performed which can dramatically improve performance.

Anyway, it worked like a charm. Vienna is now dramatically faster and my search for a replacement is over. I hope others find this tip useful!  
(Version 2.1.1.2109)