many things to address. i will just stick to midsize cars. camry accord taurus intrepid lumina etc
given the same material, a OHC engine will weigh more than an OHV, if they are the same displacement or relatively close. an OHC will usually rev higher but and OHV will get more low down torque.
styling of the mid sizers is
always going to rather bland. mazda, dodge and pontiac have the best in my opinion, in that order. but the dodge is a bit too large. the camry is just dull but the impala/ monte carlo is dreadfull. the others are marginal. honda seems to have lost the plot, styling wise, with its latest offerings, nissan is trying too hard. ford lost all credibility with that ugly fish looking thing from 98. the made over version is much better but is ugly just by being associated with its progenitor.
winner, by a long shot; mazda. that 6 is just clean and sexy in the mid size group. runner up; pontiac, but only the top dog GTP model. nice aggressive look.
interiors of the big three suck. period. the plastics look and feel and sometimes smell too cheap. the switchgear is cheap looking poorly designed (from an aesthetic, not ergonomic or operational point of view!) and just scream 80s in too much of the time. esp the GM parts.
case in point;
the generic double DIN stereo that GM has looks old, has nasty light grey plastic, and looks like its been cobbled together from assorted toy parts and leftover components from a science fiction movie. then the whole mess was painted a dull military grey. 
honda and toyota both have a plain, functional double din stereo that is finished in black plastic and looks much much better even though its just as boring a design. but it looks more coherent, is more aesthetically pleasing, and the large buttons (instead of smaller ones from GM) and their placement are more ....feng shui-ed for lack of a better term. toyotas is just a plain, boring radio found in everything from corollas to tundras, but it looks better than GMs unit.
same thing with things like HVAC and window switches. toyota camrys from the late eighties used the same window switches found now on just about every toyota with power windows, even some lexus models. the finish maybe different, but the quality seems to shine through, unlike GMs stuff which just screams 1980s like a miami vice rerun.
seat design looks newer and more contemporary in japanese cars.
the cloth used in the interiors also has the same problem. in the american cars it tends to look and feel cheaper and then retain smells better (not a good thing!!) over time. it fades quicker and gets spotted like a mangy horse if its cleaned too much. in the japanese cars the cloth is just cloth, but it seems better, looks better and lasts better. although the nissan stuff also looks like the other japanese stuff, it tends to be a little more frail and brittle. i dont know how good their interiors will be in the long run. too many people i know with rattles and squeeks from a one year old car.
winner vw passat and were talking by a long margin here folks. luxury car interior, midsize car and price.(longevity still untested.) runners up; honda and toyota.
engines. some good (mazda, pontiac GTP but its a little rough and little loud! i guess that could be percieved as a performance benefit.) some very good (nissan and honda V6s) some that could be better (pontiac base V6, toyota, fords top level V6) and some that just suck (malibu and fords ancient vulcan.)
in refinement the chevys are pretty good, the honda too, and the good ford one. so are the nissan and honda at low revs.
in power the nissan and honda are excellent. they can purr at low revs and scream at high. the top pontiac engine is good on power, but has a low rev limit (by comparison!) and is a little rougher and louder than the japanese ones, it doesnt like to rev even though it almost can.
winner honda. silky smooth powerful engines with low emissions. runners up; nissan and pontiac. runners up pontiac (torquey!) and nissan (more top end!)
handling. no questions. we're talking everyday handling and go auto crossing on weekends.
winner mazda runner up; pontiac, but the GTP only.
reliability. this is where
percieved quality can rear its head, esp for the domestics. fords tend to have a lot of ticky tack faults; steering rack, ignition, fuel tank, brakes, wipers, etc but the basic mechanicals seem to last. chevy, like a rock. period. honda. well engineered. toyota, same but questions about V6 engines and oil sludging. dodge, dodgy. nissan, durability of newer stuff still untested, but suspect. mazda, questionable
only because of relationship to ford. vw, quality problems abound but its nt well known.
winner honda only because they are less likely to rattle and squeek after ten years. runner up chevy.
thats my rant.
closing rant.
you cant compare the nissan endurance motor with the LS1 even though displacement is about the same. the nissan motor is a truck motor designed for low down torque and pulling a 5400lb vehicle. the corvette is about 2000lb lighter and is a sports car to boot. a more favorable comparison would be the S62 engine in the BMW M5. its little down on displacement, but its a large enough DOHC engine thats designed for a sports car. the AMG engines of that size are all blown, except for the last generation ones. and we dont want to compare truck/ car, last/ present gen motors.
