I cut the bottom out of one of my portafilters (http://malachi.coffeed.com/naked.html) on New Years Eve using a 2 inch hole saw after having reading about this mod for a while.
I was a bit sceptical at first but the photos and the speculation about why the coffee tastes better got the better of me so I thought what the hell. I have to say I am a convert! It is awesome to watch the pour and there is a distinctly smoother taste in the cup.
Since I only ever pour doubles or long ristrettos (short pour with double basket) the absence of the spouts doesnt bother me and in fact Id already unscrewed the spouts long ago.
The only issue I have had so far is pinhole channeling a couple of times where the water has found a fast path and sprays out of just one hole in the basket in an awkward direction. This can make your machine or bench dirty much quicker but it only means a little more clean up.
So far the results have been nearly perfect. It has taught me quite a lot about my grind and tamping as the effect of any flaws in technique are immediately apparent.
In terms of taste, the mouth feel is full, smooth and velvety. The crema tends to have somewhat larger bubbles since these arent broken down as readily compared to being choked through the spouts. The flipside is that the impressive crema breaks down a little faster.
All in all a great success and for those looking for an upgraded coffee experience, this was a really cheap one! :D