I use Twitter semi-frequently. I’m more of a reader than a poster (in the 2+ years I’ve used the service I’ve only tweeted around 8,100 times), so it’s always struck me as odd that while mobile Twitter clients (such as Plume) do an amazing job working with the Twitter API, desktop clients never seem to live up to expectations.
Timeline Position
Mobile clients reign supreme in this, the seemingly hardest-to-master part of Twitter. I follow upwards of 170 people, and when they’re all actively tweeting my timeline fills up with sometimes ungodly numbers of tweets. These days, most mobile clients remember where you left off reading, and add new tweets above that point. Then, when you refresh the timeline, you just need to start scrolling up and you haven’t missed a thing.
Sadly, though, desktop Twitter clients still haven’t figured out that this is an important feature. I really love the look of MetroTwit, Seesmic Desktop 2, Blu, et al…, however it and every other desktop client I’ve tried will either scroll you up to the top of the timeline on refresh or do the same when you quit and reopen the application. This leaves a huge mess, and you need to remember the approximate time you stopped reading so you can scroll back through the mass of tweets that have collected since.
As a side note, a large number of desktop clients will scroll on refresh as you’re reading (I’m looking at you, MetroTwit). If I’ve just refreshed and scrolled back over 50 tweets, it really sucks to be scrolling up as I’m reading only to have the client force-scroll down as another 20 tweets come in.
View Conversation
A great feature in Twitter’s new website redesign is the ability to click on a tweet, and a tab will open up beside the timeline showing you the contents of the tweet, other tweets by the person, and most importantly, if the tweet was an @ reply to another tweet or series of tweets, it will show those as well. Mobile clients typically allow you to tab on a tweet and have the conversation show up inline, or in another view, but once again desktop clients have missed the boat on this one. MetroTwit requires you to right-click on the tweet and go through a few levels of context menus before you get to an option to show the conversation, and most lack this feature entirely, making it difficult, if not impossible, to find out what each of the 15 new @ replies are referencing. So far, Blu appears to be the only client to provide a quick-view of conversations similar to mobile clients.
Image Previews
Another feature of New Twitter is ability to click and tweet and Twitter will show you, in the pop-out tab, a preview of images linked to popular sharing sites like TwitPic. Mobile clients will typically add a small thumbnail (and some, like Plume, will allow you to view the image without leaving the client, as below).

Once again, the only desktop Twitter client to do this is Blu. The others still require you to click the link, switch to your browser, and then switch back to the client. Why not just use the Twitter website, then?
Your Retweets
Ever want to see which of your tweets have been natively retweeted? Unless you’re on twitter.com (or using Blu) you aren’t likely to find out. Even mobile clients fail at this one, despite the fact that native retweets have been around for over a year.
The Takeaway
So it might seem like Blu is the ultimate desktop Twitter client, seeing as it actually does most of the things listed here, right? Of course not! Much like other desktop clients, Blu lacks the option to configure most of it’s settings (there are exactly three options on its Settings page, and one is font size). Don’t want toast notifications? Screw you! Want to make the mouse scroll wheel scroll fewer than a page at a time? Up yours! Adjust the colour scheme? We’re blu(e)! Have more than one column, change the auto-refresh options, or tweak the font size (alright, they can do the last one)? Go to hell!
The TL;DR of the matter is, if you want a good desktop Twitter client, stick with http://www.twitter.com – it still has the most features, is less annoying, and doesn’t suck as hard.