[sudarshan_sar]

This is a great plugin and I love being able to open URLs and search google, amazon etc without actually visiting the landing page first - like hitting 'o-g <search>' or 'o-a <search>' for example. However with the support for multiprocess not being there, I decided to move on to vimfx which is somewhat more minimalistic and less easily configurable compared to vimperator, but in my experience so far it is really smooth even though it lacks that particular feature(among others) that I highlighted earlier in the comment(well not entirely, you can still google search in a similar way). Overall though vimperator was/is a great plugin, especially for people who are really used to vim and hate switching to mouse for browsing the web.

[autocorr]

That's something I ran into as well, but actually has had a solution in vanilla Firefox for a while. You can create keywords for searches by right clicking a search box and selecting "add keyword for this search", and can then be used in just the same as vimperator by typing that keyword into the navigation/awesome bar (such as with VimFX). One advantage to this is that you can create a bookmark folder of search keywords, and they'll sync across all your devices thru Firefox sync. I find this especially handy on Firefox mobile.

[wsha]

This is a nice feature. The downsides compared to Vimperator/Pentadactyl is that you can tab-complete the search term and you can't get search suggestions as you type (or at least I haven't gotten either of these things to work).