As they are drawn now and as they are always going to realistically be drawn, it's horrendously unrepresentative. Yes, in this magical fantasy land where Republicans and Democrats actually come together to caring about electoral reform, proportionality, and open election laws, it could work, but that's not going to happen. As it stands now, doing things the Maine-Nebraska way would heavily stilt the election against the Democrats.
If we said, used US house seats for a parliamentary system, they'd actually be pretty representative by international standards. IIRC, the average house district seat is like R+1.5, which is largely due to the Voting Rights Act creating 40 all-black districts. And even then, being +1.5 tilted in a direction isn't really that bad.
For really amusing parliamentary districts, you can look at Manitoba. Where the PCs need to thwomp the NDP by around 10% in order to take a narrow majority. Or Singapore, where the PAP could still hold an majority if they managed to lose 40-60. Or Japan between 1945-1993 (the districts were even funnier because they were multi-member districts). A grimmer example is the South African Nationals triumphing in 1948 (and instituting apartheid), despite losing the actual popular vote by around 38%-49%.