Although we would all like to think rival bidders are lurking in...

Although we would all like to think rival bidders are lurking in the background I think it's helpful to remember that BOW management have been talking to interested parties for months with no apparent success. Arrow would have every right to ask very pointed questions if suddenly it emerges that BOW have been secretly negotiating with other parties while ostensibly negotiating in good faith with themselves. IMHO the only possible rival bid would come out of left field and would be hostile to Arrow without any suggestion of being part of the strategy employed by BOW to eke out a higher offer.
Remember that BOW has engaged some very capable advisors in all this - Wilson HTM have been in CSG since day one and have always been more upbeat than other brokers so it probably stands to reason that $1.52 is all we'll get. Certainly the market thinks so as it is trading below the offer price - always a good barometer to what may lay ahead.
However I see no reason to sell out yet, the offer is pretty much guaranteed so why not sit back and see what transpires over the next few months. The market is about as unpredictable as it gets right now so anything is possible.