the Aquanot and the sentry are as different as night and day....
I can almost guarantee you that the Aquanot will last forever and pump out a ton of water..
the Sentry is good till the year warranty runs out..thats it and it only pumps
maybe a one-fifth of what the Aquanot can do.
if you put the aquanot on a separate drain out the side
of the house into the bushes, you have added extra security
in case the main sump line were ever to freeze..
both pumps will fit down in the hole, its no big deal
I do it all the time