1) Worst onshore salaries and treatment like bonded labors. 0% consideration of your skills or domain, if you are looking for a domain specific work, run away, look else where, they do not have any focus or inclination to develop on this, origins of this company lie in Fusion Technologies the older name for this company which was a consulting firm aka body shopper, now it just wears a cloak of an offshore company, branding may have changed, but functioning did not. All they want is cow, that should start giving them milk moment it is in their farm house :)
2) Higher your CTC amount shorter the bench time-out you can have (get into a project or get fired). No matter what domain technology you have if you are not getting placed in X number of days, they will start harassing you and would do cloak and dagger tricks with you, make you re-write your resume for each client and tune it to their requirements. That's where your career would take a dive. They even fake client interviews, synechron folks from onsite, will call you as clients to harass you, give in to shift your technology, since you are not getting placed.
3) I have seen a C++ Developement Lead get a Java Lead position, you can only understand what you would expect from seniors in this case. There are SQL Lead developers working as Java Lead Developers.
4) No matter how hard or how smartly you work, the one who licks, finally wins, your work has nothing to speak about, unless you are irreplaceable. All huge hikes are given to the buttlickers - 97% of the cases.
5) If you are coming from a big or process oriented/ policy based company, Synechron is a (paid) media hyped company, that lacks foundation, no ethics, no employee friendly policy, no benefits, not even a good canteen for food, I can go on and on ... If you are coming from a small company it is little bigger (in size only) than small, so may appeal to you.
I am a level headed, ego-less techie (developer at heart), I got hired as a Lead, had to leave at the same designation. Basically here you do a sort of contractual jobs, or mini projects, projects keep on changing for you every 3 to 6 months as they finish, and you get onto a new totally different one - it is good for folks who want to be jack of all (technologies/domains) trades and expert of none (technologies/trade). If you do not belong to this category, run for your life.
They have a very nice way of keeping you away from getting any sort of growth, basically even if you have worked hard and put your best in the project, but you are not like them, moment the major developements gets over you would be the first one to be put on bench. This trick is also used by Managers during appraisals time - they will deliberately release you from the project and put you on the bench, during appraisal period, so they get to show an excuse that you are non-billable, and hence your appraisal would get screwed.
Body shopping ethics run strong in this company, there are no rules on their onsite pay, I have had first hand experience of being paid ridiculously low for my year tenure at onshore, their salaries offered are so low, that you would barely be able to sustain yourself, you might end up ruining your personal life as there is too much workload at onshore, you work 12 to 14 hours and also on the weekends. You will not be able to save anymore than you will in INDIA. At onshore the worst part with them is totally un-supportive offshore setup, everywhere onshore person has to suffer or adjust to offshore managers terms, you end up working 12-14 hours/day - ruining your personal life and you get paid 1/2 the salary of a regular developer (yes you will be paid much less than a simple developer of that client company, and you may be working as an expert or a lead). Basically here be prepared to work 12-14 hours a day and get paid for 4 hours a day as junior developer much less than your actual position / capability - simple :)
As far as I understood this companies business model, they get good rates on putting you on staffing project on the clients side, pay their employee half or less than that, rest all in their pockets, and seems this money saved is used to help them sustain lavish bonuses and company cars for upper tiers, and new monthly (chicken) hiring.