I use a Quadra Thru (cheap, reliable, no external power needed) and a Blokas Midihub as a programmable router.
Total of 4 inputs and 7 outs, with some creative routing of THRUs on some machines it’s been enough to connect quite a lot of gear (synths, pedals, MIDI controllers) with no noticeable latency.
The OP could also daisy chain from their friend’s gear. In my limited experience, latency isn’t that bad even at five or six devices, if they’re modern. The “no more than three” guidance you may come across is from the early 80s. YMMV
This would work for a small set-up:
OP’s box with clock OUT -> Friend’s box IN
Friend’s box THRU -> friend’s other box IN
friend’s other THRU -> OP’s box without THRUThe music here is awesome. John sco field and bill frisell coming up in next couple of months. Theatre is great also.
depends on amount of transmitted data.
in case it’s only messages like note on/off, program change, etc – everything’s fine.
but if something like parameter movement/automation is involved – chances for latency and/or timing issues start to increase.
Good point.
Yep I also use the RK-006 for my mobile setup. Really great device and very flexible. Can generate its own clock, and do sync pulses/merging etc.
I see it as in between basic merge/thru boxes and higher end stuff like the MRCC and iConnectivity stuff.
Superb value, super tiny. Only gripe is you end up with a rat’s nest of cables. BUT it’s actually good for group jams in a circle since you get a ‘spokes’ layout of cables!
well there is also the added benefit that if MIDI is on it’s own type of connector, you can’t accidentally plug MIDI into an audio path. The is also why it’s good that we use Speakon for high power speaker cabinets and not 1/4" or XLR like in the 70’s.
A 3.5mm jack is an inferior connector in every single possible way, unless you need your connectors to be tiny.
I’m allways afraid that I break one and that it will be stuck in the socket. 
If you are going to daisy chain, it also matters of what sort of “THRU” is being used in the daisy chain.
On the plus side, if it’s a “hardware THRU” (ie: a dedicated port labeled THRU) then it would be the same as using a MIDI THRU box and could easily take part in a daisy chain with no appreciable latency or jitter impact (A compliant dedicated THRU is just an electrical connection, no micro-processor involvement).
On the negative side, if it’s a “software THRU” (aka: echo OUT), then it merges the data coming from the MIDI IN with any data that the unit itself wants to potentially send out. That requires a microprocessor to manage the data stream, and then timing integrity does start to break down relatively quick. (especially Clock signal, which becomes more noticeably impacted sooner by jitter than other data). It’s dependent on a few things though, impacted by either the micro-processor itself, or by the code it is running. How intensive processor utilization is while performing all other tasks is one major factor, and what efforts have been made to prioritize incoming and outgoing clock data. Also, how much data is being added to the signal. No matter how modern a piece of gear is, there’s a bottleneck for serial MIDI that’s still from 4 decades ago.
I usually use a dedicated MIDI THRU box (QUADRAs mostly) just because most gear I seem to have these days lacks the dedicated hardware MIDI Thru port. MIDI THRU is just like adding a dedicated hardware THRU with the added benefit of being able to distribute the signals in hub/spoke instead of daisy.
If you are handy with a drill and soldering iron, you could easily add 3.5mm jacks alongside the DIN jacks.
Engineering is all about compromise, you can tell someone is an engineer because they infuriatingly reply “it depends” when normal people would say “inferior in every way”. 
Sorry if I was unclear - I was commenting on @4517’s comment that you quoted.
There are many reasons why DIN is preferable to 3.5mm TRS. But if you mostly send MIDI around on 3.5mm TRS then it does make sense to buy something like the RK-006 or mod DIN devices to have 3.5mm TRS MIDI.
Its fantastic. So much functionality.
Yep really can’t recommend the RK-006 strongly enough - totally excellent device that gives so much for such a good price. Never had any stability issues or any flakiness either. Works great for DAW and standalone use cases and is so flexible. 10/10
I use one, it’s great!
I also strongly recommend the Retrokits RK-006