Ive had a several BARs come through and currently own 3 BARs. My currents are a Mk2 Stalker in 7mm Rem mag, along with a 30-06 and 308 both are type 2's. I've had a Safari with sights, Longtrac stalker, Longtrac oilfinish, all in 30-06, Safari with BOSS in 30-06 and 300 win mag. In the family we have a rare 270 weatherby Safari and a new Safari no sights in 30-06. All worked well with smooth actions except a few issues with the Type 2's.
BOSS Safari rifles: BOSS worked as advertised and loads could be tuned nicely. Mild recoil in both calibers. Extremely loud and mad muzzle blast, especially the 300 win mag.
Mk2: Composite stalkers are nice and come with iron sights. I dont have to worry about scratching during bushwhacking. Feels heavier.
Safaris: Nicest of the bunch and older one came with iron's. Feels the heaviest and hard to lug around. 1) protecting the stock 2) its heavy. Solved with a double sling.
Longtracs: Lightest and most accurate of the bunch. More composite parts like trigger guard and floor plate. Not sure how long it will last under heavy use. Should be ok though if taken care of. Never hunted in very cold weather.
Type 2: Oldest and luckiest of the bunch. Least accurate...2-3" avg at 100yrds but Ive seen them at a lucky 1"ish before. Can probably be tuned if I put the effort in. Gives me a few issues. The 06 worked well when bought new in 1991. Up until the mid 2000's, started acting up. Would fail to eject and feed when below freezing. Change out all springs, works fine now but stays home mostly. I keep it because it's got too much sentimental value. It's been everywhere. Approximately 2-3k rounds through it. The 308 had all problems that could go wrong with a BAR. The buttstock loosened up eventually which also caused play in trigger group, scope mount screws protruded, forestock is loose and touching barrel on one side, poor grouping (5" at 100yrds) with all ammo. I decided to work on this gun as it somehow had a soft spot in my heart. I disassembled it all and tightened up the stocks front (took some fitting and woodwork) and back. Forestock screw torqued ( had to to do a lot of testing and tightening) to achieve optimum groups. Scope mount screws filed back. I'm keeping this one as a dedicated iron's shooter. She's good now but groupings still in an honest 2-2.5" avg at 100yrds. Not the best but these two Type 2's have killed everything I've shot at and is why I am keeping them.
Best ammo I've every used in all BAR's is standard factory by many names Federal Classic, powershok, nontypical. Groups better than any reloads I've made. Much cheaper and kills em just as dead. I now keep reloads for my bolt guns only. I have not handled a Mk3 or a pure Made in Belgium, Assembled in Belgium BAR and would like to add to list one day. If I was to pick one BAR, I'd pick the Mk2 Composite Stalker. Comes with irons, still built with metal and has the features of the new and old. Weight falls within the mid range of all BARs and if I had one in 30-06 or 308, I'm sure the weight would come down some. This is why I still have the Mk2 7mm rem mag. Happy BAR shopping!