Hi there and welcome.
Honestly, I don't think you are going to find any reviews or comparisons of any current or recently current commercial models. Most people in cafe situations only have the experience of 1 (their current machine) and don't have anything else to compare it with until they upgrade to a new one. Then they only have a comparison of a worn out older machine, and a new one either of same brand or of different brand or model. The comparison is not valid, and when going from one machine to another you become accustomed to the new one and leave the old one behind.
Also, cafe people don't really write reviews....they work in a cafe, and the machine is a work horse, it gets used, it gets worn out, it gets upgraded. In a busy situation it should realistically be upgraded every 2 years, usually because by that time things are starting to need rectifying and will eventuate in down time when you should be selling coffee instead of repairing something... In business, the machine is a work horse, not an object of desire and the result in the cup depends on operator expertise not black magic inside the box
. Think of taxis...they are a workhorse and drive according to the nut behind the wheel !
Where you may find reviews is in special interest internet forums, where domestic use end users buy worn out / older cafe use machines, restore them, and write about it. They are usually older (often prehistoric in commercial use terms) models that you would never ever put back into a commercial situation and are not available to buy except usually in used, clapped out condition, so any review is irrelevant to a cafe owner looking for a machine.
I think you need to be quite pragmatic in your approach when looking for equipment to be used in a business venture....in my opinion there is no room for emotive decisions, and if possible a new machine is best.
That is: You have said words to the effect that there are a number of lever machines around.....I would reply....not really in terms of for business use. If you have been reading the forums yes, there are a number of levers around but they have sprung up in the recent past, from all and sundry, to cater to the enormous amount of discussion
in retail end situations. The amount of discussion in these topics makes it look like there is a lot of genuine interest in the market place for such, when the reality is not so (from my own personal experience). An equipment vendor can fill its showroom with lever machines because it seems from surfing the net they will walk out the door in bucket loads, while the reality is there is only a very small percentage of people that will buy...99.9% of individual posters to lever discussions on the web will never buy one despite they make it look like the interest in lever machines is absolutely mammoth.....to put it another way, it isn't, and it is more the domain of special interest "equipment-o-philes" in home use situations rather than in business. That is, it mostly just talk.
In terms of buying a lever (or any machine) for business....I would advise you to find out what manufacturers are represented in your area, and make enquiries with them as to whether they offer a lever model. Buy one from a reputable brand name / importer that seems as though it can offer you after sales support should it be required.
In light of what I mentioned above, be realistic...if your locality is one where a small pocket of "lever interest" has resulted in these machines being locally available well and good, but its also very possible that no one may be importing lever machines to the area. Some dealers will have lever machines in the manufacturer catalogue but wont have any on the floor, and you may have to order one. Most manufacturers will only build lever machines on order, so you may have to wait the required time for it to be built and exported to the local dealer to sell on to you.
I hesitate to give brand names because it's better for someone in your situation to find out what brands are locally (to you) represented, first. Besides.....if you choose a reputable / well known professional use equipment manufacturer, then the machine will do its job if you know how to drive it. Ideally, if you have good name equipment then its actually not about the equipment...its about the coffee.
Hope that helps as a starting point, and good luck in your venture.