<< if you've ever read any reviews on the sentra you'd notice they say it has a lot of power, but no where to go with it because it handles terrribly. it never wins any car comparisons. if you want something with a lot of power, a crappy interior, and crappy handling, get a sentra (read the reviews). >>
I think you should read a few more reviews yourself. Although I personally would prefer a Mazda Pro-5 for the utility, the Sentra SE-R's reviews are not as bad as you describe. It did fare poorly in C&D's comparison test but overall it has gotten pretty good reviews. Edmund's gave it their #2 "Econosport" award (behind the Jetta 1.8T), Motor Trend , CarPoint, and Canadian Driver all had good things to say about it, and the regular Sentra won MotorWeek TV's "Small car of the Year" award for the second year in a row. Most of the reviews I have read like the handling characteristics of the SE-R and the layout (although not the colors) of the interior.
By no means do I think the SE-R is the end-all of cars under $20K, but it seems like you are basing your opinion on one or maybe two articles.
Edit: some quotes...
"Handling is excellent, with a stiff, serious-minded suspension and razor-sharp steering. And the 180 <sic> horses do this light four-door proud. Understeering through a tight turn? Just power your way out: The Spec V's helical limited-slip front diff will tuck the nose in and guide you through." - Motor Trend
"Cornering is flat and confident, particularly in the Spec V due to the its sticky, low-profile 17 inch radials." - CanadianDriver
"Assembly and finish show great attention to detail, but the XE and GXE are definitely more bland inside that the sportier SE-Rs that feature red trim...
...the dashboard looks good and is well organized. The controls are legible and within easy reach...
...the multi-link beam suspension provides excellent stability in most situations, and the Sentra bites into corners of all diameters, producing high lateral acceleration especially in the SE-R...
...the SE-R's bucket seats provide lateral and lumbar support worthy of a competition car..." - MSN CarPoint
"Dynamically, the Spec V was a standout, with responsive and well-weighted steering, flat and neutral cornering and strong, even braking." - Edmunds.com