To give you a little background for this review, first, few words of introduction.I am not a professional photographer; however I consider myself experienced amateur.I have been into photography since film, starting with 35 mm mirrorless cameras, then moving onto SLR and then, when first digital cameras showed up, I bought my first, under 1MP point and shoot.Currently I own Canon 20D, 40D, 70D and 5DMkII. I also had a brief encounter with Nikon SLR as well as own several point and shoot digital cameras, including underwater and 3D.I also print quite a few of enlargements at home using Canon large format printers (13x19).My photography subjects include landscapes, cityscapes (both daytime and nighttime), nature, aerial shows, people, astrophotography and various others.I do not shoot weddings and usually do not do typical portraits and my animal photography experience is somewhat limited.I am not a pixel peeper. I do not tend to overanalyze photos and do not usually do extensive technical tests. For me it is mostly about look and feel and the perception rather than technical data.Now, to the actual review.I have owned this lens since 2006 so I have had some time with this and took quite a few pictures with it until I bought the 70-200 f/4L IS. This is the lens to which I will be making most of my comparisons.This was my first of the lenses I purchased together with 24-70 f/2.8L and with Canon 20D.My initial impressions were very good. It felt pretty solid, the focus fell fast enough and, being my first IS lens, I was very happy with the handholding at the high end of the zoom.The quality of pictures I was getting very surprising to me. They were sharp enough; colors were really nice and overall I could not complain. This was of course long time ago and with 20D.Then I purchased 40D and was even more happy with the lens for quite a few years until someone talked me into 70-200 f/4L IS.Recently, I got into shooting aerial shows and some bird photography and started missing the long range; therefore before jumping into buying something else, I decided to revisit this lens.This is one of the very few times I did some extensive comparison tests and here is what I found out.Pros:Gets you that long reach wen needed yet short end not too bad on full frame.Comfortable in handling. Not too heavy and has a zoom lock.Very good color reproduction. Not the type of 70-200 f/4L IS but it cost less than half of that lens.Very sharp in the middle of the frame. Quite close to 70-200 f/4L IS on 5DMkII. Not so much on the 70D. When comparing it to 70-200 f/4L IS, both on 70D, the difference is visible, but at 100% view, and smaller sizes get quite close. I did quite a few comparisons from tripod in pretty challenging indoor light conditions, at f/5.6 and 100 ISO and I am quite impressed after all these years. This is all in full 100% view. At smaller sizes differences are much less noticeable. I would say that for prints up to 8.5x11 most people will not notice the resolution difference. Sharper than the EF-S 55-250mm f/4-5.6 IS STM, which I also own, at comparable focal lengths, especially at the long end.Does not get too soft at the long end.Autofocus fast enough if you learn how to use the lens and camera combination. I had so few out of focus photos and get less of them the more I used it. Not sure if I would risk it for aerial shows since I have 70-200 f/4L IS and it works great for that, besides of course missing the longer focal length (more crop).IS works very good and helps quite a bit, especially at the long end.Decently priced.Cons:Gets little soft when you move away from the center. Little softer at the long end but again not that much.Not as sharp in the middle on crop sensor (70D) as it is on full frame. This kind of surprised me but at the same time it needs more light at f/5.6 so should have been expected I guess. Again, this is at 100% view.Autofocus and IS noisy, especially compared to newer IS zoom lenses.Lens hood not included. Yes, I will put this as con, because Canon hood is not cheap and when I bought it there was no aftermarket available.Neutral:I am not so concerned with vignetting as newer cameras can correct for this pretty well or you can do it in DPP if preferred. It has some but in general gets corrected very well and if you shoot crop sensor or crop full frame photos it should not be an issue.No manual focus in AF mode. Some may consider it as con but I almost never do that especially on long zooms. If I use manual focus I switch to manual focus, therefore this is not a problem for me.Conclusions:Very good general purpose long zoom lens.If you shoot full frame, want to save some money and especially if you crop a lot in the middle of the frame, I would not hesitate to recommend this lens to you.On the 5DMKII on comparable focal lengths it was as sharp in the middle as 70-200 f/4L IS was on 70D.If you shoot crop sensor, then the verdict depends on whether you are willing to spend twice as much on 70-200 f/4L IS or almost four times as much on 70-200 f/2.8L IS or try some other options out there.The difference in quality of photos may not be as noticeable as you think, however the handling difference would be quite substantial in favor of 70-200 f/4L IS.Will I keep it? Maybe, it depends on whether I really will want or need ;-) more reach than 300mm.If I decide that I do not than I will most likely keep it and use it more often going forward.Attached below are few sample photos. Unedited, just some with 50% Digital Lens Optimizer applied. All taken with 40D.