Welcome to CS.
You said "middle east", in which case I dont know why you are not considering any of the Turkish brands, which will do the job admirably for a micro roastery EG the Toper Cafemino is in your size, works well, and is far far better priced.
For the rest of it. My personal view is that atleast one of the three you mentioned is one of these "internet manufactured" icons, the kind where anonymous internet posters talk brands and models up and around and into the stratosphere and turn them into icons and recognized names, despite that no one can check their bonafides (those that talk up the brands). Its very expensive for what it is.
The other two, while they are very long and well established, quality roaster brands, are now I think trading on their past (meaning, there are others that have caught up in the quality stakes and possibly even surpassed them and will be better priced).
Honestly for such a small start up size, where you say you are testing the waters, I dont know why you would zero in on the most expensive of brands, and it should be possible to purchase a (for example) Cafemino for around half the price of anything you have been quoted, for a roaster that will still do the job very well for you.
All that said, no one can answer what size of roaster to buy and what brand. You need to do the research that is applicable to your situation, and no one else can do it for you. That means you need to contact the manufacturers themselves and or their agents local to your area, and go see them and get referrals to their happy clients so you can ask them plenty of questions and see if they will suit you.
Regardless, I woudnt worry about going to the european brands/better technology until you have finished testing the waters and know what your next step needs to be. Having expensive, latest technology roasting equipment becomes more important when you get up to the bigger sizes.
Also consider that you will be able to buy a 5 kg Turkish roaster for less than the prices you are being quoted for 1 kg machines above.....Not that I am saying you should buy one straight up as I dont know anything about your situation other than you have mentioned in the above post. You need to do your homework, and really, do the major part of it off the key board by talking to manufacturers and their agents and actual users of their equipment.
Hope that helps.