It's not quite that simple. I wish it was and want to tell you buy the D4S but I want to be honest and open too.
The D4s is an impressive metal frame.
There are tons of upgrades all over that are better than MakerBot.
For example, the X axis idler is already ball bearing on all D4 models.
The Z stage is the all new metal design and bigger linear bearings VS the MakerBot with plastic Z arms and bushings.
The Wanhao D4 series extruder (same on MK9 or MK10) is similiar to the Replicator 2 but no chance of the drive gear slipping on the motor shaft (supposedly fixed on newer Rep-2s)
Comes with a glass bed stock and is heated.
Comes with a genuine Meanwell 350 watt PSU
Comes with a complete enclosure
My only gripes are:
Still use a PTFE lined hot end, but they do work for PLA or ABS.
New D4S might come with a funky bootloader that means that updating to Sailfish might require a programmer.
The Replicator 2 has the best all metal hotend money can buy. This extruder can print nearly any plastic type.
Also a metal frame
Cons:
no heated bed
Stock PSU cannot support a heated bed
Single nozzle
Acrylic bed stock (no upgrade to glass bed inlcuded)
No enclosure
Replicator 2X:
Has my least favorite hotend for PLA. "Designed for ABS printing"
Has a heated bed but no glass upgrade
has an enclosure
Most expensive.