I'm going to touch on Duo and Haris in PanOceania in another post, but (in short) I don't see a lot of value in most of our Duo options.
I'm not a PanO player but recently I've been interested in MO. Montesa Duo looks like a reasonably strong alpha strike -- you start in good range bands for both heavy weapons (and even for spec firing a light grenade or two if you need to), and it doesn't take up your whole list like the Hospitaller link does. Do the Montesas not see much table for reasons besides the sculpts being ancient?
They do have new sculps. Plus Montesa DUO is usually at least 100pts and ~1-3 SWC. Thats quite of investment for a DUO which might be in trouble if enemy has a decent repeater coverage (or if someone like me forgots that enemy has AD with climbing+ xD). On top of that you have "compulsory" 60 pts invested in TO sergeants (TOFOOS+TO MSR), that's 160 pts already ;) Still can sometimes works wonders if you take enemy by surprise, but it's quite fragile on itself (maybe that's why it's less popular than "robustness" of Hospitaller link or similar approaches).
I'v tried a duo of Father Knights (AHD) with a pseudo-haris of Magsiter ML + Magister + Hospitaller-doc and a duo of Santiagos (BS + Spitfire) a few times now and won't do it again. The duo-team of Santiagos is great, while the Father Knights are a totally overpriced brick. But the pseudo-haris failed for me. The ML died directly because of the low BS and then the link is useless. To have a better ARO-piece, i added a third Magister and a Hospitaller HMG now in addition to the Santiago-duo. So not that different anymore from what is always played.
There are some arguments for the Santiago and the Montesa Duo, but both are resource intensive and questionable in their utility over single units. The order efficiency of Duo has some weight for the Santiago Spitfire + Paramedic Duo, but suffers from being an expensive way of delivering a weak specialist. The Montesa Duo largely suffers from the size of the investment, and questionable improvement over the impact of a solo Montesa.
I'd suggest the Santiago duo has the added advantage of negating Frenzy on a gunfighter you want to do a lot of work with, the specialist is just an added bonus for when you find you've run out of targets.
Problem is that Santiago DUO is not a Swiss Guard. While it costs much more than a single Swiss, it has not the power of the Swiss Guard. Don't get me wrong BS14 Spitfire HI ARM4 W2 is not bad... but so are linked sniper/Sin-Eaters etc. HMG Swiss Guard has much bigger hitting power than a Santiago plus an amazing camo state which itself can solve several issues. What I'm saying that usually MO do not have that great "fire superiority" singular units, and does it by linking Hospitaller HMG (to create effectively BS20 HMG, something which is almost better than a Swiss Guard (depending on victim)). Oh and MO is designed not to have too many orders (compering to NCA/ASA), in a way of AVA1 Fugazi and Order Sergeants (their cost).
I have used Duo Montesa very effectively with ASA. I think you can do the same great job with them in MO, if even better since you have access to TO and not only Camo. The thing is to not deploy it against something that can throw you E/M Grenades too easily but you can do wonders in holding ground scenarios with those guys like Safe Area or Frontline. As for the Santiago Duo, I think they aren't the main attack piece. They are better for second or third turn assault, when the big pieces are down and you still need firepower to deal quickly with REM/LIs/MIs or subpar surviving HIs. The fact that the Spitfire Lt only costs 1 CAP supports this. They are here to speed up in and out. They can be really good in Supplies too to rush opposite DZ and kill the box carriers and steal them. Teutons would be nice with a Duo too with a Spitfire to deliver his EXP CCW carrying friend to the target and begin the onslaught. I think you can really work in MO with a core of OS as a long range active piece and then use your multiple Duos to move up easily and grab what you can before hiding and wait for the next active turn. Maybe something like this: Military Orders ────────────────────────────────────────────────── GROUP 1 10 ORDER SERGEANT Heavy Rocket Launcher / Assault Pistol, Knife. (1.5 | 15) ORDER SERGEANT Combi Rifle / Pistol, Knife. (0 | 13) ORDER SERGEANT Combi Rifle / Pistol, Knife. (0 | 13) ORDER SERGEANT MULTI Sniper Rifle / Pistol, Knife. (1.5 | 21) ORDER SERGEANT Paramedic (MediKit) Combi Rifle / Pistol, Knife. (0 | 15) TRAUMA-DOC (Father-Doctor) Combi Rifle / Pistol, Knife. (0 | 14) PALBOT Electric Pulse. (0 | 3) KNIGHT OF SANTIAGO Paramedic (MediKit) Combi Rifle, Nanopulser, E/M Grenades / Pistol, DA CCW. (0 | 41) KNIGHT OF SANTIAGO Lieutenant Spitfire, Nanopulser, E/M Grenades / Pistol, AP CCW. (1 | 44) MACHINIST (Father-Engineer) Combi Rifle, D-Charges / Pistol, Knife. (0 | 15) PALBOT Electric Pulse. (0 | 3) SPEC. SERGEANT (CH: TO Camouflage, Infiltration, Forward Observer) Combi Rifle, Antipersonnel Mines / Pistol, Knife. (0 | 27) GROUP 2 4 PATHFINDER DRONBOT Combi Rifle, Sniffer / Electric Pulse. (0 | 16) PATHFINDER DRONBOT Combi Rifle, Sniffer / Electric Pulse. (0 | 16) FUSILIER Hacker (Hacking Device) Combi Rifle / Pistol, Knife. (0.5 | 18) SIERRA DRONBOT HMG / Electric Pulse. (1 | 25) 5.5 SWC | 299 Points Open in Infinity Army