Toughest (rock-solid) Online No Limit Players? (all sites)

[Desdia72]

online poker seems to have alot of excellent limit ring game players. however, NLH is a tougher game to dominate, IMO, particularly big limit SNGs and MTTs. who are some of the toughest online NL players (whether ring, SNG, or MTT) you've faced?

ex: many people think Neverwin (who i hear is *dumbanimal* on PP and UB) is a beast at the limit ring game tables.

what (NL)player do you cringe when seeing him/her at your table. would it be Grandiose (NL ring games)? what about Prefontaine/Spirit Rock (NL ring games and $5000 HU SNGs)? or Erik123? what about SNGs or MTT players?