If you don't want a motor drive then the MD-4 isn't much better than the MD-12 although in my opinion the grip of the MD-4 is somewhat better. If you use it as a motor drive then it offers the following features.
1. It takes 8 AA the same as the MD-12 and run at 3.8fps not much faster than the MD-12.
2. If you use the MN-2 rechargeable battery then it can run at 5.5fps with the mirror functioning (6fps with the mirror up).
3. It powers the F3 so that the 2 little coin cells inside the F3 is not used. There is a catch. The F3 will not function if you attach the MD-4 and don't put batteries in it because whenever you attach the MD-4 the camera doesn't use its own batteries.
4. You have power rewind.

I'm just not a big fan of 50mm lenses in general.... Every camera came with one back in the day, and some are excellent... but to me they're pretty boring. I tend to leave them at home and - when I take out one of my old Nikon cameras for a spin - usually take a nice Nikkor 35mm f/2 to use instead (and have similar 35mm or 40mm lenses in other vintage systems).

The 55mm macro is another matter. Always nice to have a macro lens, even if it's only the 1:2 capable, f/3.5 version.

I'm looking forward to making more extensive use of the 105mm.... I've only used one a few times. Seems like a great lens.... at least lots of folks appear to think so.

I'll reserve judgment on the Series 1 70-210mm for now... It's an all-metal beast and happens to be one of the Kino Precision/Kiron-made versions (22xxxxxxx serial number), which are generally pretty good (I've used their 24mm f/2 and various macro lenses in the past). It's a later model that lacks the "ears" to interface with the metering system of some of the earlier Nikon film bodies (EF, F2), so I'll have to learn how that effects it's usefulness on them or if it would be better just used on the later Nikon (FM2n, FE2, FG). EDIT: I just looked again and see I was wrong... the 70-210 does have the "ears", so should be usable on both older and newer Nikon bodies.

As I understand it, the Nikkormat EL from 1972 was the first electronic Nikon body and the first to offer Aperture Priority AE. It's from the era of "full size" SLRs... roughly the same and heft as other SLRs from the early 1970s time period, including the F2 (... and Canon FTb, F1 and Konica T, T2, T3, etc.) There was also an "EL/W" version with provisions to mount a simple, rather slow film winder. The EL uses a now rather rare PX28 battery, which Nikon did a superb job of hiding in the floor of the mirror box. (Took me a while to figure out exactly where it was and how to open the compartment cover!) The Nikon EL2 that followed in 1977 was one of the last of the full size SLRs and abandoned the Nikkormat (Nikomat in Japan) naming convention that had previously been used for the more consumer-oriented models.

From 1965 to 1978, in addition to the EL series (AE capable, aperture priority), there were also Nikkormat FT-series (all mechanical with built-in meters using a manual "match needle" method of adjustment, much like the F) and the Nikkormat FS (no internal meter). The Nikkormat series cameras basically replaced the Nikkorex F of 1962, Nikon's second SLR model and a more consumer-oriented, meterless SLR designed to share lenses with the original, pro-grade Nikon F from 1959. However, the Nikkorex F was actually built by Mamiya. In part this was probably done to gain access to the then new Copal Square, metal-bladed, vertical-travel shutter, which was the product of a joint development effort of Mamiya, Konica (Konishiroku), Pentax (Asahi Kogaku) and Copal. Yet the revolutionary new shutter was first used in a Nikon camera, which wasn't actually made by Nikon themselves! The Nikkorex F also ended up selling under Ricoh and Sears brand names (Ricoh Singlex and Sears SLII). In a sense, the Nikkormats were Nikon asserting itself and bringing all their camera production "in house".

The late 1970s and early 1980s Nikon FE, FM, FG, FM2/FM2n, FE2 etc. were all somewhat more compact models.... As were Canon A-1, AE-1, AE-1P and Konica TC, T4, etc. Minolta and Pentax both also shifted to smaller SLR models around this time, too. Probably this was their respective manufacturers' response to the market success of the Olympus OM series, which set a new standard for more compact SLRs and lenses that consumers really seemed to appreciate.

Love these old cameras!

Now if I can just get my friend to part with his F3!