I live near by and would agree with Sue, as she says there have being some closures recently but new tenants have come in such as Argos and Boots. There is a good mix of shops in the centre but the Tesco is not the best and I think if they could sort it out, it would increase immensely the center's appeal (There is another Tesco's down the road in Artane which is a model store). The new extension is grt and has really brought up the look of the whole center. Wife loves Tempest, and Hughs and Hughs have a book store with Costa beside which is grt IMO.
It does have a good catchment Santry, Beaumont, Artane, Whitehall etc etc. Its good for causal shopping but if on more serious trip I think most people would either go to the Pavilion, Blanch or the Valley. The center seems to do decent business and seems busy most times I'm there but not rammed.
One word of Caution IMO I would be nervous on taking a letting on upper fall of mall if looking for passing trade , unless being given very good terms since a number of stores have closed up there, IMO they need a few more big name stores on the 1st level of mall to draw people up there I would guess 80% or more of footfall do not visit the 1st level at all.
Best of luck whatever you decide