3rdworld.
I have 657 flights on my 2 m pattern model with each of the engines you have mentioned.. It's a light version of the 2m Slingshot design ( Big Shot).
The engines I have used are OS 140 RX 260 flights. This ran really well. Usual bearing changes after 70 -100 flights and a new ring after about 350 flights( 200 in a previous model). Fuel 15% nitro 18% Coolpower. Usually ran a 16*14 APC at 7600-7700 rpm was getting 7900 rpm on a 17*12 APC but didn't like that as much.
Then got a Mintor 170 - 03 model. After 16 flights it wouldn't transition from idle- even with the fuel line squeezed and this engine was replaced with an 04 model. This ran a 17*12 APC at 8200 rpm with Mintor 95 gm Al pipe and 8100 on 16*14 APC. Generally had problems with loading up at idle before and during take off. Mostly OK in the air but mid range was pretty rich even after I had backed off the pump screw. Power was awesome but after 216 flights the con rod broke. Rebuilt the engine but after second start two of the lugs holding the cylinder barrel to the crankcase broke. Engine was returned to the supplier and was rebuilt. It's sitting in a box until I get a mantlepiece to mount it for an ornament. Have lost confidence in it. Other problem was the rear brging lasted about 116 flights and it can only be replaced as a genuine spare for $95 Australian.
Currently I have 165 flights on an OS 160 FX. Using a Perry pump and the Mintor pipe. This arrangement has been great. Virtually identical power to the Montor 170. On 15% nitro, 20% Coolpower I am getting 8150 rpm on 17*12 APC, 8100 rpm on 17*13 APC - suggests the pipe was a bit long for the 17*12 and about 8000 rpm on the15.5*12 4 blade APC. Had to back the Perry Pump out about 2 turns from the factory set and the engine transitions well and is very reliable. First start of the day on its back because plug tends to flood- probably from Perry pump which I don't run dryat the end of each day. After that no dramas. Original brgs lasted 60 flights then replaced rear with a stainless one. This rumbled after another 60 flights and currently I have 45 flights on stainless front and rear brgs. Only problem with the 160FX is its a bit heavier than the OS140 RX about 100 gms from memory. My Lite Shot currently weighs about 4450 gms so weight is not a problem. Will be using this engine in my next plane.
Don't know about service in your part of the world but apart from bearings the OS have been very reliable. My ranking is OS 160 FX, OS 140 RX then Mintor 170.
Happy flying. CW