Okay, I need to correct a couple things above.
First, the Express Package makes the bow ride high. Everyone knows this. The tank schematic provided by Hapehour: shows the tank float is in the back of the tank. This means I would use a considerable amount of gas before the back of the tank dropped enough to show movement on the fuel gauge. My new "gallonage" is now closer to 3 gallons per hour with HEAVY tubing, not 2. Not a major deal, just correcting past posts on this.
Also, this weekend we had a full boat (full house? Wait, that's poker) for the first time. 6 adults and 6 kids. With that number, top speed dropped from 35 mph (with 2 adults, two kids) to about 25 mph. Tubing brought it down to a nearly painful 20-21 mph tubing. Tubing worked, but the motor was really weighed down and it took full throttle almost all the time. The 6-9 year olds were fine with the ride. The 13 year olds didn't have NEARLY as much fun. The solution was to drop half off at a beach for a while. With a half full boat or less, we're able to send a couple 13 year olds on the tube airborne off of wakes.
So, just saying the 115 uses more gas than I thought due to tank design and a bow-high position, which fooled me until I had enough experience with the setup. And the power of the 115 HP is marginal for a full boat of people.
Just wanted to report this so others considering purchasing this combo know what the trade offs are and what they may be getting into. I do not have power OR hydraulic steering, and while the 115 HP is a little hard to turn, it's not that bad. I do a lot of circles and figure-8s when pulling tubes, so I do turns quite a bit. But, if you're thinking about buying a similar combo, and decide to go with the 150 HP, from what I hear, you will want to get the power steering.
Would I buy the same package if I had to do it all over? Well, at the time we purchased the boat, the 150 HP Verado with DTS and the power steering option would have put it at about a $5-6k upgrade to go with the 150 HP. Mercury has a new 150 that is substantially less. If you could get by with hydraulic steering instead of power (test drive them both), then the incremental is more like $4-5, I think. Some one can correct those numbers for future readers, that's just what I remember, and my memory on those numbers ain't the best.
Knowing what I know now, it would still be a tough decision as to whether the extra thousands $ would be worth it. Test drive, test drive, test drive!