there's a few pecularities about Russian airliners that need to be taken into account:
1) In the Sovjet planned economy, aviation was an important key area of the so-called "military-industrial-complex" and as such it had lots of state support in the allocation of ressources (manpower and materials), but on the other side of the coin, it was also subject to operate in a classified environment.
2) For strategic reasons, the Sovjets separated the design process of any aircraft from its manufacturing. Antonov, Ilyushin, Tupolev or Yakovlev are design bureaus, and not manufacturers. I.e. these famous instances are in charge of developing new aircraft types, from the drawing phase to and including the building and testing of the first prototypes.
Apart from this task, the designers are not directly involved in the mass production of their designs. Once a type was considered ready for market introduction, the Sovjets allocated the actual manufacturing of an aircraft type to one of the many aircraft factories spread all over the huge country. A lot of them were and still are located in towns and cities behind the Ural, where the Sovjets considered the factories save from "imperialistic attacks" - they had learned their lesson from WW
-II when the Germans occupied the traditionally more industrialised Western and Southwestern parts of the USSR
3) Unfortunately, the same also goes for maintenance, as Heavy Maintenance is usually carried out either by the factory that originally built the airliner, or designated "aircraft overhaul factories". The result is that the same factory might be building or maintaining Tupolev airliners on one line, and Sukhoi fighters on the next line.
This basic structure of the industry never changed in the post-Sovjet times. Except for the complication that some desing bureaus and factories suddenly found themselves in different countries of the CIS (Antonov is now Ukrainian, the Tashkent Aircraft Production Organization TAPO - which builds Il-76s - is now in Uzbekistan and so on...) Thus customs and hard currency suddenly began to play a role as well in the already stretched-out production process.
5) Now about the output of the design bureaus: If one thing deserves to be admitted, then the fact that aerodynamically, the Russian airliners are among the best-designed aircraft of the world. Yet, one also has to admit that this often is their only real strength. The powerplants usually lag way behind Western counterparts, and most if not all Russian airliners are really really massive, and thus heavy.
6) True, that massivenes makes them so sturdy that you can land an Il-62 on a grass runway (it happened) or take-off with an Il-76 from any reasonably flat frozen area of water (it happened). But it often imposes a fatal penalty on payload vs. range. I recall discussing with a Western based integrator's representative about using the B757F vs. the Tu-204-120S (the freighter version with Rolls Royce engines & Western avionics). He told me they had indeed evaluated the Tu-204S - until they realised that they could either carry a little over half of the tonnage the B757F would carry on the 6-7hrs segment in question, or else they'd have to set the 204 down for a fuel stop halfway into the flight...
The high dead weight and the inefficiency of the power plants are - so we are told - both a result of the Sovjet metallurgy not being able to reproduce the kind of light and sturdy metalls developed for use in the Western air & space industry. I bet they spied and tried hard, but they didn't manage to handle the processes and temperatures involved.
7) A fore-poster has already mentioned maintenance in general as one factor speaking against Russian airliners. Maintenance can be done on almost any type, if you are willing to send it back to where it came from, and to wait 3 months, 4 months, half a year for the beast to come back with a new lease on life on it.
Of course, that will only happen if you are willing to pay first (otherwise the factory cannot buy the necessary parts!). Same for ordering a freshly built airframe: Once you forge over the money, the factory can start working on your plane...
As a side note: Back in the Sovjet times, before sending a bird to heavy maintenance, you better also took out any custom items - such as advanced avionics you had upgraded your airframe with - as the factory would send your bird back in pristine condition. Without your gadgets, that means. Ask any former Interflug mechanic about the "Carl Zeiss" built precision instruments they installed in their Tu-134A. After the first one came back from MX
with the old Russian instruments re-installed, Interflug Technik had learned a lesson...
8) Speaking about instruments, that leads me to a final point which makes it difficult to find customers for CIS airliners outside of their traditional markets. I can understand that few airlines outside of the USSR
wanted to fly the older types that all feature 3-man or 4-man cockpits with metric gauges in Cyrillic...
Hope there's some food for thought in the post, cheers, Lukas