I believe the feds suspended their pensions for new employees quite a while ago. They have a thrift savings program that will match contributions, but the day's of 75% salary in retirement are over.
As for other fed benefits, I've known people who worked for the feds and they say the benefits are not that great. There is quite a high monthly premium for medical and dental.
The pensions were available for employees hired under the old retirement plan (CSRS) prior to 1983.
In addition to social security, there are two benefits: the "basic benefit" and the "thrift savings plan" (TSP).
Now the formula is (Average of highest three years of compensation) * .01 * (years of service).
Feds must also reach the minimum required age (MRA) to obtain full benefits unless the govt is downsizing or eliminating your job (whereby you can retire early). The MRA for those born after 1970 is 57.
So, an attorney retiring now within middle-management probably makes about $140,000. Lets say the person has worked their entire adult life for the feds except for 5 years (about 27 years). The annuity (basic benefit) at age 57 would be $37,800, closer to 25% - 30% of your pay.
The TSP is similar to a 401(k). 1% of your salary automatically goes into your retirement account. Additionally, the govt will match your own contributions (up to 3% of your pay check) by 100%, then match your own contributions by 50% for the next 2% of your pay check. For example, if you contribute 7% of your pay to the TSP, the government will match 4% of your salary (3% matched $1 for $1, the next 2% matched $0.50 per $1). In addition, you get the automatic 1% contribution. So, total deposit to your TSP account: 12% (5% from the govt. 7% from you).
My understanding is that the other "benefits" are typically no better than most law firms, except that you actually get to USE your vacation time (and federal holidays). Benefits are different in certain locals, as well. For example, I live in DC and get a public transportation subsidy of about $100 a month.