Pros
Associates are given the opportunity to get hands-on legal experience with real cases, going to court on their own, conducting depositions, writing substantive motions, interacting with clients, etc. (although no trial experience). Additionally, some partners are willing to take some time to train associates. For this reason, it's not the worst place to start your legal career for a year or two. But I certainly wouldn't think of a position at Wilson Elser as a career or long-term placement. And it seems like the management agrees, as associates are essentially treated as just another cog in the machine.
Cons
Billable hours are essential to any insurance defense firm. The difference between Wilson Elser and other defense firms, however, is the emphasis placed on billing requirements. At Wilson Elser, it's a mantra, it's gospel, it's essentially the only thing that partners and other management want to discuss with associates. This would be understandable if the compensation was reasonable given the amount of hours associates are expected to bill. But at Wilson Elser, associates are required to bill a MINIMUM of 2100 hours, yet get paid nothing close to what other firms requiring the same billables pay. In short, associates are expected to bill big law hours yet get compensated small firm pay. This explains why morale is so low among associates. It also explains why the firm is literally a revolving door, with a new associate leaving each month. If you have no other options, this isn't the worst place to work temporarily, for the reasons mentioned in the Pros section. But I would choose it as an ultimate last resort, at least unless the firm's compensation becomes commensurate with its billing mandate.