If you are going to run a 2 meter or dual-band mobile and must park in an indoor garage, a roof mounted 1/4 wave or short dual-band antenna "usually" out performs a 5/8 wave mounted lower on the vehicle truck deck. Larsen, MaxRad and Antenna Specialists all make commercial grade, heavy duty dual-band whips which can stand repeated bashing into fire sprinkler heads and low overheads.
But the biggest bang for the buck for an economy mobile antenna is the www.hamstick.com
cellular look-alike dual-band mag mount with the 18 inch "pig squiggle" whip and 3" mag. mount. It's been a fine performer for me. I carry an FT5100 dual-band mobile with a 17ah gel cell battery, and heavy duty fused cigarette lighter plug cord with in-line noise filter in a Pelican case, so that I can use it in whatever agency poor car, rental vehicle, etc. I want to put it in.
Sweeping the hamstick quarter-wave, economy dual-band antenna with my MFJ-469 I have found that it's very broad banded and it works very well on high-band VHF and marine frequencies, as well as the 460-MHz public safety band and GMRS. Everybody should have one of these as a spare or loaner antenna in their jump kit!