I liked their reporting, it's one of the easiest ones I've used and is reliable. All of my clients liked it. BBM works really well for very basic accounts with a few campaigns. You can basically set and forget.
Not really sure where to start - I guess that they advertise Google and Bing data connections but don't let you know there is no Bing Shopping. Not only does their reporting software not connect to Bing Shopping, it can't even bring it in for budget or reporting purposes. I am an eCommerce marketer, I use Bing Shopping for 6 of my clients and there was no work around for reporting. Because of this I tried to cancel, but they refused and I had to retain a lawyer. They refunded my money and now keep charging my card every month. I tried to get them to stop, but they don't ever answer their phone no matter when I call and I've called 3 or 4 times a day on at least 6 different business days. They are an ethical nightmare.
BBM does not work well on shopping campaigns unless you want the same bid on all products in a campaign. For search, it doesn't allow you to make bid adjustments below the campaign level. If you have 500 keywords in a campaign, they will all get the same bid or blanket bids - there is no way to prioritize certain keywords without putting them into their own campaign. For anything beyond simple accounts, this is a nightmare.
Supposedly there is a way to have "budget only" on campaigns, but I was never able to get it implemented. I was also given an Account Manager and told I would have one when I signed up. Once he was fired or quit, he was never replaced. All of their promises and communication are done over the phone, nothing is guaranteed in writing. The Account Manager I had never escalated any of my requests or even remembered anything I asked him, he obviously did not write anything down. Just a bad, very negative experience with a company that costs $899 per month.
Make sure you really give the trial a thorough evaluation, because even if they assure you that you can get out of the contract if it isn't a fit - they will fight you tooth and nail. Get everything from them in writing.