Bob Revolution Duallie double stroller ?'s

Our son is 2.5 and our second son will be born in May.  We already purchased a Fisher Price Stand n Ride duo double stroller that is like Baby Trend and Joovy Caboose sit n stand strollers for everyday use. 

I am very interested in getting a swivel wheel double jogging stroller for walking but am wondering if I really need it if I have a sit n stand double stroller?  How comfortable is it to do some serious walking on a regular basis not just an occasional stroll around the block with a sit n stand?  I have baby weight and then some that I am finally ready to really work on taking off after this baby is born.  I lived in new england for the last 4 yrs and could not get outside to be very active for very much of the year and look forward to being back in the south now where I can be out and about pretty much year round. 

I fell in love with the features of the Bob Revolution Duallie the other day at a little boutique, but don't know if we should invest in such a pricey stroller if the sit and stand would be totally sufficient for walking.  If it helps we live at almost sea level with very little hills so I would be walking on mainly flat surfaces streets and sidewalks.  I like that the footrest area is extremely extended because our son is very tall for his age and with most joggers out there his feet would have no where to go or could get in the way of the front wheel.  I also love that there are individual sunshades and they also extend much longer than traditional jogger sun shades.  This would allow me to cover the baby well but also have the other shade adjusted differently so my toddler can see out very well if he wants too.  All in all this looks like a great stroller and would handle very well too.

Also I'm wondering about how true it is you can't use a jogger with babies until 6 months old, unless you buy the car seat adapter for the Bob of course to use it right away.  The Bob does say you can use it at 6-8 weeks old without the adapter but if you were to be jogging or going off road you couldn't use it without the car seat adapter until the baby is 6-8 months old.  I won't be jogging because I have severe exercise and allergy induced asthma and simply cannot run.  But going off road is more likely for me like taking it to the beach.  The adapter of course is a additional cost and I'm wondering how worth it it would be to buy if we did get this stroller.  I could see not buying it and just waiting 6-8 weeks to put my baby in the stroller as long as this is safe. Thanks in advance for your opinions!