Given a choice of either the Veritas BUS or the Veritas Custom #4, I would plump for the #4. This does not invalidate the BUS, just that the #4 has a wider range for the experienced.
There is no doubt in my mind that the BUS is a really terrific smoother, and that it is super easy to use and set up …. much more so than the #4. Hone the single blade (I recommend a 25 degree primary bevel and a cambered 50 degree secondary bevel). The resulting 62 degree cutting angle will perform very well on just about all you can through at it. However … BU high angle smoothers would best with thin shavings, and with the grain. As a finish smoother with reasonably predictably grain direction - even if this is interlocked - the BUS should work well. I think what appeal most to many today is that they set up so easily, and will little fuss. Back when they were my go-to, the reason for choosing them was an economical high angle plane.
The Custom #4 is more complex to set up - along with other similar BD planes with a chipbreaker - in that one needs to know how to set the chipbreaker close to maximise performance. This is not a big deal, but does scare off some. With a closed up chipbreaker, one iis rewarded with a plane which can work in any direction, such as into the grain. This is especially important when planing the intersection of book-matched panels, where the grain direction is opposing.
My Custom #4 has a unique frog, at 42 degrees. This produces a 42 degree cutting angle, which is low … too low to use on interlocked grain without a closed chipbreaker. The advantage of a low cutting angle is that it leaves a smoother finish. Having stated this, in practice, hardwoods do not show this up as readily as softer woods. The finish off a high cutting angle on Jarrah is not readily seen compared to that off a lowish cutting angle.
How important the BD plane is depends on how much you plan to use the chipbreaker. One needs to keep in mind that many - most? - users pre-2012 used their BD planes with common angles (45 degrees) and had the chipbreaker pulled back. How is that different from a BU plane with a common cutting angle (33-35 degree bevel)?
Regards from Perth
Derek
it's very difficult to make recommendations:
1) to someone who has probably made up their mind already
2) when you gauge that the chance of getting beyond taking thin shavings is just about nil
What comes to mind, and sometimes I forget this, is that the person who got me into woodworking had four LN planes at the time (perhaps 5). the only one that he could get to work at all was the block plane.
this was around 2005, before there was any instruction for planes of note on YT, and maybe there wasn't really YT yet. I found YT extremely early because I had been watching another video site that had humorous videos on it every day, and it got hijacked. it was called compfused or something of the sort and it only had what would be called shorts now, as well as custom flash.
So all of this information, generally at the time you had to get a DVD if you wanted to get anything, around $15-$25, and frankly, some of them were really no good or were just VHS from as far back as the 80s transferred to DVD.
I also got the BU planes, and two of them in total, and the potential seems like it's there. they're simple, you can put a steep pitched iron in them and take thin shavings. they need sharpening more often than a plane with a cap iron because of the mechanics of the planes, but they're limited pretty much to that. Sure, you can hone one with a low effective angle and trim end grain with it, but over a longer period of time, much of that ends up in the vise and a #4 does great with it.
If anything, the BU planes sort of took the place of vanilla planing and having a separate high angle plane. What strikes me from that period in hand tooling is I bought everything I could find, but one change in weather in an evening after gluing up panels or case sides and you were in for a war the next day.
I just put together a painted loft bed for my son. it's 4x4 pine on the corners and the rest is SYP, right off the rack. to get paint on it, you need to fill whatever voids there are and you can plane it before that, but it's going to move and the filler is abrasive, so it's off to sanders for ease. I broke my normal habits and getting annoyed with ROS sanders (I have a pair, one is a 6" dual mode monster and the other a festool ETS finish sander), I bought an old used milwaukee half sheet sander. It's probably what I should've bought instead of the dual mode.
So my comment to the original poster, if a bevel up plane is all that's ever needed, I think the abrasive setups now are better. that's from my real life experience with a gaggle of high angle planes, scrapers and the bevel ups. There's just always something limiting around the corner.
Finished surface is often brought up - I don't know who is supposedly contending that the surface isn't bright enough off of a bevel up plane. On maple, it's fine. It may be slightly lacking on cherry, but not to a level that anyone would ever care. On maple (which "polishes" easily), I don't remember ever seeing anything. it's the ability to remove wood beyond thin shavings that's lacking, and I suppose to do it on softer woods.
I am not being anything less than totally serious when I say that you could do a whole lot of fitting and better faster finish sanding with one of the lower high tension lower speed belt sanders (the locomotives) and the half sheet types with a low cushion foot. And they wouldn't care if panels moved a little bit. single drop shop sanders were also very popular - no clue where that discussion went.