Pros
Friendly and open environment. It's fast-paced and things evolve quickly - the vision evolves as fast as the eCommerce industry does, and so your focus today may be very different from your focus in 9 months time. The recent SAP takeover hasn't really impacted the culture a large amount at the moment. I progressed from a Professional Services consultant in the UK to a Product Manager in a year - not anticipated when I started, but hybris is one of the few cultures where, if you grab the opportunities when they come, you can pretty much carve out your own career if you have the aptitude.
Cons
Not a place for people who need to be told what to do. You need to be a real self-starter, and you need to network and make use of resources to get the best understanding of the organization (which changes shape frequently) and the product / product roadmap. Consequently, it's not hugely systemized as in order to be agile, the company tends to adopt technologies that are easily adaptable (e.g. the Wiki guides everything!) This is changing slowly, but creakingly slowly - and the integration with SAP is helping this somewhat. The takeover by SAP has inevitabily introduced some conflicts where there can be mixed messaging from the SAP side of things - but again, this is not nearly as bad as I anticipated (having been through four mergers before). The most annoying part of the culture can be the some cliquey nature, where you do get little enclaves of coolness - but these quite often don't get the chance to become ingrained due to the way things get shaken up on a regular basis. Also, I'd say that because there can be a lot of change, teams can sometimes seem to be pulling in different direction - there isn't really clear leadership from the top - it tends to filter down in such a way as people have their own take on what it means and implement as they see fit, which can cause a lot of friction until consensus starts to form. Not always hugely efficient - more of a Darwinian model in many ways! But usually the best way forward wins out eventually. Some of the niceties of corporate life can get neglected sometimes - this is very much left to individuals and individual offices to sort out (e.g. charitable work etc) but this is beginning to very very slowly change.