The Ebbtide 188 SE Bow Rider 2010 is a deep-V design and the Ebbtide 2100 SS FC O/B 2009 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
On paper these two are close siblings in the size department - Ebbtide 188 SE Bow Rider 2010 at 18,3 ft versus Ebbtide 2100 SS FC O/B 2009 at 21,0 ft. Weight tells a clearer story for trailering families: the Ebbtide 2100 SS FC O/B 2009 tips the scales at 2 660 lbs - 510 lbs less than the Ebbtide 188 SE Bow Rider 2010 at 2 150 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
Both boats share a closely matched power ceiling - 190 hp for the Ebbtide 188 SE Bow Rider 2010 and 200 hp for the Ebbtide 2100 SS FC O/B 2009. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup. Fuel capacity breaks the other way: the Ebbtide 2100 SS FC O/B 2009 carries 45 gallons versus 20 gallons in the Ebbtide 188 SE Bow Rider 2010. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Ebbtide 2100 SS FC O/B 2009 is rated for 12 passengers, while the Ebbtide 188 SE Bow Rider 2010 caps at 8. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Ebbtide 2100 SS FC O/B 2009 could be the deciding factor.
Bottom line: Choose the Ebbtide 2100 SS FC O/B 2009 if your priority is putting more people on the water - it handles 12 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Ebbtide 188 SE Bow Rider 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 8 that costs less to run day-to-day.