Despite being a very happy 6S user, I completely agree with
@alfredus here. The DE89 and similarly derivatives are excellent razors, when paired with the right blades and the right technique. I always chase and generally get BBS - occasionally with some damage but there's not much of that these days. What I have found is the following:
- A mild razor like the DE89 requires a sharp / aggressive blade to work well for me, preferably changed regularly to keep it sharp. Otherwise, it's too mild / inefficient - it's easy to miss bits at the right angle and regrowth comes in too early. However, if you get this right, it's also the most "mindless" shaving option - if your technique isn't perfect it won't bite you too hard. The perfect option for a bleary eyed workday shave where you can't really be arsed / don't have enough time but you need to shave regardless. Probably needs 3 full passes and touch ups to get BBS but they can be quick passes if you need them to be.
- An aggressive razor requires a smoother / less aggressive blade option if you want similar results - although technique needs to step up a notch to avoid damage - particularly pressure. It will be more efficient but it will also be less tolerant of mistakes. Requires fewer touch ups / passes to get a BBS but they need to be done slower and more carefully to avoid blood, resulting in no real speed improvement. Lots of cheap blade options to choose from here though and you can be a bit slack about changing them so often. My Fatip Grande with a Lord blade springs to mind as a good (brass) option here, if you can tolerate some poor tolerances which can leave the blade at an angle in the razor when you tighten the handle. By the way, the most aggressive plate on the 6S doesn't really qualify here - it's more of a middle ground in terms of overall aggression, which is not a bad thing as long as you aren't expecting the fully spectrum in one razor option.
- You can pair an aggressive razor with a sharp / aggressive blade (my Feather Artist Club with a Feather blade is the ultimate expression of that) and it will be very efficient and give an excellent BBS - but your technique has to be spot on and it won't tolerate mistakes. Don't go down this route without being tolerant of a bit of blood because that is how you will learn how to improve your technique! I use this option when I'm not rushed and just want to enjoy the act / experience of shaving, as well as improve my skills / technique. Not such a good option if you just need a decent shave in a hurry... which is most of the time for me these days (unfortunately).
- A mild razor with a mild blade just leaves me with stubble, so that's not a viable option in terms of the BBS I require.
If I had to pick just one option from the above, it would undoubtedly be the first. It's just the most practical solution for me on an everyday basis. So, if you are looking for better / more efficient results, make sure you start out with testing some sharp blades in your DE89 first eg Feathers. Personna Lab blues work a treat in that razor for me too for some reason, although they are too sharp / aggressive for most of my other razors. Having said all that, in agreement with previous posters, if I had to pick only one tool razor to shave with for a lifetime, with value being a factor, it would be the 6S. Stainless is a good thing and I love the weight too.