It is really sad to see Unimax FOV going under. For the large part, they made excellent items across a variety of scales and were a true and long-lived leader in small scale militaria. I couldn't decide on any single FOV item that was my favorite... As I look about my study, there are FOV items all over the place in different scales. Therefore, at the risk of making a long-winded response, I've gone through and listed my favorite FOV releases by type and scale
1:700 Scale Ships
USS Enterprise (modern) aircraft carrier -- this was large, detailed, had large contingent of planes that could be placed about the deck, and was affordable!
1:72 Aircraft
V-22 Osprey/F-14 (retooled) tossup -- The FOV 1:72 planes from all eras were hit and miss. Some were accurate and excellent toolings and others were not so great. The V-22 was one where I felt they got the detail and quality right (save there was no "Marines" stenciling on the fuselage!). Their retooled F-14 was based on the Century Wings tooling meaning you could get something close to that quality for almost half the price. I've not felt the need yet to get a CW F-14 (or even a Hobby Master or other premium one) because the FOV F-14 is just that nice to me at least.
1:72 Armor
M2 Bradley/German Panther tossup -- The FOV 1:72 armor was very well done and had a lot of great subjects. Their pieces were generally functional with moving tracks and turrets and usually had a crew figure or two that added life to the model. I always liked their 1:72 Bradley (Enthusiast edition) due to the small details like stowage in racks, etc. The 1:72 Panther had fantastic detailing and I loved all the moving parts, right down to the bow machinegun.
1:72 Figures
US Modern Soldiers -- These were almost more accessories to their 1:72 armor than anything, but they were really the only affordable 1:72 figures out there and could go with all the other armored vehicles and aircraft made by other companies. I particularly liked the US modern soldiers for some reason.
1:48 Helicopters
The AH-1W Supercobra -- To me, this was the one where they got it right... Good paint job and nice mix of detail and function on the model, and an accurate tooling. The UH-1 Huey would be a close second for me.
1:32 Armor/Vehicles
T-34 (first series) -- Rating the 1/32 armor is extremely tough. FOV had a huge variety of WWII Axis and Allied as well as Modern armor. Then there were all the support vehicles from the motorcycles and jeeps to the trucks and halftracks. This scale was their bread and butter and nearly all the vehicles were well made. But I chose the first series T-34/85 tank as it came right in the middle of the golden period for FOV when you got a museum-quality model with an excellent paintjob/weathering, lots of working details, and a ton of accessories for under $50. I've been so happy with that T-34 that I never did get another one... A lot of tanks from this period - the Pershing, the Panzer IVs, Jagdpanther, Panther, T-72, etc. - had that excellent mix of detail, function, and quality that later releases like the M-24, Sherman Firefly, Jagdtiger, etc did not quite have.
1:32 Aircraft
P-39Q -- This had the best tooling and detailing of all the FOV planes, which were otherwise not that great. I believe Unimax entered the 1:32 aircraft market as a way to compete with 21c, BBI, Corgi, Hobby Master and others that were already making pre built models in that scale. The FOV 1:32 planes had a lot going for them: opening engines, opening cockpits with figures, moving control surfaces, retractable gears, swappable ordinance. Save that for as good as their armor was is about how bad most of their planes were. Inaccurate designs, huge rivets, funky-looking ordinance, and I could go on... The only aircraft they really got right was the P-39 which fits right in with all the other premium models out there.
1:32 Figures
Ages of Action Figures (all of them) -- FOV made a ton of figure sets in 1:32 scale that got better over time from those wonky "popeye" style figures to their later offerings which were realistic and nicely scaled. Their Ages of Action series with the Romans, Knights, Vikings, Pirates, and US Civil War soldiers were particularly well executed with excellent detailing and sculpting and figure variety.
1:18 Armor
M1 Abrams/German Tiger tossup -- FOV did have that 1:18th scale Bravo Team line and for the large part it was quite well done. Yes their 1:32 tanks had more working details, but the big tanks still looked the part. I was always a fan of their 1:18 M1 Abrams, particularly in the heavily-weathered desert scheme from Iraqi Freedom. With some stowage and other minor modifications, it is a really good-looking tank and to me looks better than the BBI M1. The German Tiger lacks some details like spare track links and tow cables that could have been added to it, however, it gets points with me for actually being an accurate mid-production Tiger with zimmeritt (and in SS markings to boot). The 21c 1:18 Tiger by comparison was a mish-mash of features from early and late production tigers and didn't have the zimmeritt.
1:18 Figures
Bravo Team US Army/USMC -- I love the Bravo Team modern figures and got a ton of them when they were readily available at Target. They were fantastic for the price with detailed, articulated sculpts and lots of accessories. Nearly all my modern vehicles are crewed with the Bravo Team figures. I cannot quite say the same for the WWII US and German figures, which while still quality sculpts, were just never as accurate as the 21c and BBI examples to warrant widespread use. Unimax also made those excelent premium action figure lines with the Ages of Action figures, Assassians Creed, and I think one other line. Those were excellent figures as well, but never had the versatility for me that the Bravo Team ones did.
1:16 Armor
M4 Sherman -- I have the FOV 1:16 Sherman and Whitmann Tiger (Villers Bocage version) but not the King Tiger. Both are absolutely fantastic models and the crown jewels of my small scale armor collection. I like the Sherman the best, however, because it is nearly all diecast and has full detail all the way through. The Tiger has a plastic hull and if you look way inside the interior, there are some parts/equipment omissions like the turret MG grip/receiver and periscopes that should have been there. While certainly not a deal breaker (and hard to see unless you look way inside) those same parts are nevertheless to be found in the Sherman. Plus the Sherman had the tank rider figures and all the stowage.