By far, the biggest disadvantage to Sikich is their healthcare plan. Sikich offers only one plan - the high deductible plan. The premiums are about $100/mo if you're single (which isn't so bad); but those costs jump to $600/mo for family coverage. There are no co-pays, so you pay 100% of costs until the deductibles are met. Individual deductibles are about $3,000; and family are just over $5,000. So it's possible that between the premiums ($600 * 12 = $7,200) and deductibles ($5,000), health insurance can cost you over $12,000 per year if you're on Sikich's family plan.
The 401k match is fairly basic at just 2% of your salary. Vesting is 20% each year; fully vesting after 5 years.
At times, it can feel that the Naperville office gets too much attention. It's a little frustrating when many of the trainings and meetings are conducted live in Naperville, while the other offices have to watch them on a computer screen.
Work gets a little more political once you get into the manager-level positions. Whenever the firm brings in outside talent at that level, it seems to ruffle some feathers with current managers. It can also be disheartening to watch certain opportunities go to the same few guys over and over again.
One of my biggest peeves about Sikich is that they put a clause in their engagement letters that if a client hires a Sikich employee, that client has to pay Sikich a fee equal to 30% of that employee's new salary. This can limit an employee's options if they decide to leave Sikich.