It depends on what you want to do. The IIgs is a faster IIe, but many of the 8-bit people prefer the IIe because it's more true to the original platform, plus IIGS can be a little on the expensive side. And if you're using the weird graphical 16-bit computer component of it, you usually need to buy potentially costly memory and CPU upgrades.
This is a good point about the IIgs that bears repeating: if you actually want to use it as a "IIgs" with its native operating system you really should *at the very least* look for a system that has some sort of hard disk solution. (Preferably Apple's SCSI card, or one of the third-party IDE/CF Flash cards.) You'll also want, again, at the very least a ROM1 system with a fully maxxed-out Apple stock memory card (This configuration is often described as having "1.125MB" of RAM) and if you really want to get "serious" about things you'll end up buying a third-party 8MB RAM card. In short, owning a IIgs was a lot like owning a low-end Amiga like an A500; you can play self-booting games with a stock out-of-the-box floppy-only system but to really use it as a serious computer you have to basically double the cost of it with additional peripherals.
However, I will note this in the IIgs' favor over a IIe: If you don't care about IIgs software but just want the equivalent of a fully maxxed-out IIe system a floppy-only IIgs system might cost you about the same anyway. If you're comparing basic systems with just a system unit and a couple of floppies the prices for the two are in about the same ballpark, and the nice thing about the IIgs is it has the equivalent of a Super Serial Card (which you'll *really want* with a IIe) and a CPU accelerator (which drives up the price of a IIe immensely) built-in. It's when you add a hard disk controller and other upgrades really needed to run GS/OS that the price of a GS goes through the roof(*). Where I think the IIgs fails in the comparison is simply aesthetics: a IIe (or older) has a really iconic, retro look that instantly tells even casual observers that what they're seeing is something oldschool and special. The IIgs... not so much.
(* Cory mentioned the FloppyEMU, and for casual use that can serve to give you a taste of running GS/OS on a more basic IIgs system. But that's still $100, which on one hand I consider perfectly reasonable for a well-built hobby device, but on the other might not be something you'll want to spend on something you're not even sure you're going to care about.)
Personally, as I may have mentioned elsewhere, I don't care much for GS/OS applications. The OS is technically somewhat interesting and in some ways is actually more advanced than the MacOS of the same era but the hardware limitations of the system, particularly the painful 200 line vertical screen resolution and sluggish stock CPU speed, frankly sort of trigger some not-so-fond memories of running
GUI software on IBM PC/XT-class systems with CGA graphics. 640x200 graphics are a thing that I just can't be nostalgic for.