A bird in the hand and all that...
Actually it's on the low end of the scale for your experience, but as it's a small firm you should see quicker returns on your investment if you add value to the business - i.e. much easier to gain seniority. Also smaller firms tend to be good places to shelter the storm right now - they operate closer to their respective markets, have lower overheads etc, and client side are often perceived to be more cost effective/justifiable as less footfall of junior staff on projects.
Big 4 and the other big firms are not the best place to be right now - far easier to cull people in large numbers. Compact and bijou - same as the offer.
As Achilles said in the Odyssey, it's better to be a slave in heaven than a king in hell, at least right now.