I have a reservation for a one way car rental ( mini-van) from Seattle to Laredo Texas. The best rate I can find is with Advantage at about $426 plus another $30 for an additional driver charge. I don't know much about Advantage but was attracted by the rate. Today I found a similar car ( minivan ) from Avis for about $536... with no additional driver charge because he is my domestic partner.
Of course I know Avis and their reputation.

Is it worth saving approx. $100 and going with Advantage or should go with Avis and their reputation.

I really try to avoid Advantage. Long lines at pick up, hard sell on upgrade, hard sell on gas purchase, and they actually charge extra (unless you notice and decline) for roadside service if their car breaks down. Every other car company I've rented from includes that for free.

I don't like Advantage either, but that price difference is pretty enticing!

Well, first thing to notice is that $426 + $30 = $456 vs $536 which is only $80. The more you chip away at it (maybe with Avis discount codes of some kind if you haven't tried that already), the less that difference may get. I actually have zero experience with Advantage, but it doesn't sound good and would probably be inclined to spend the $80 if I had exhausted other options for getting a better price from Hertz, Avis or National. Heck, I'd probably try others like Budget and Dollar first. I've had reasonable experiences with Dollar in the past (though I haven't used them recently).

Anyway, I gather you've tried different locations in Seattle? Given that it's a one-way, I assume you don't need to pick it up at the airport. With one-ways it might be trickier to assume which location is cheaper, but it's worth trying different ones to see if there's a difference in rates. And if you haven't already, have a look at the Avis forum for discount info.

I have used Advantage several times in the past. Unfortunately they are very similar to other companies in trying to upsell you to higher car categories (that they would give you free anyway since they don't have your category available), trying to sell you all the optional coverages, etc.

The main difference I noted with Advantage compared with the larger companies is that they charge your credit card at the beginning of the rental for the full value of the rental. Not sure if you would get a credit if you happened to return the car earlier.

I would rent with them again. I just always check my rental contract with any company before signing it to be sure rate is correct, optional coverages are appropriately declined, etc.

Generally I have had very good experience with National for one-way rentals. You might want to try them for the fun of it.

I've never used Advantage, but all of the 2nd tier car rental companies seem to be the same. In addition to the comments already made, 2 more factors to consider. One is if the car breaks down en-route; chances are the majors (Avis, Hertz, Budget, etc.) are more likely to have a location nearby and able to switch cars. Also the majors tend to have cars in better shape. A more important consideration is that the 2nd tier companies tend to be sticklers for damage if you decline their CDW ... very quick to charge $1000 for a new windshield if a rock happens to nick the windshield during the trip, for example; also for nicks in the paint from road debris (not accidents). While the majors ignore that and treat it as normal wear and tear. On a cross-country highway trip you have a pretty good chance of getting some rock chips on various parts of the car.

I called National this morning and with a few dicounts their rates are also favorable....but... they charge you with a $8 a day addtional driver fee....which adds up on a 7 day trip. Avis does not charge anything....

Join National's Emerald Club (I believe you can still do so for free) and your domestic partner can drive your rental without paying an additional fee. I have used National almost exclusively in the last two years and they've almost always provided excellent service.

Otherwise, pay the extra $100 and go with Avis...the hassles of third-tier rental agencies that others have described here make using a big-name worth it.

Apparently this is definitely a case of YMMV.

I rented from Advantage in Denver a couple of years ago and received a car that had 10 miles on it.

I rented from Avis in Vienna, Austria and they socked me with a claim of $450 in damage for a 1/2" scratch near the front passenger wheelwell. Fortunately I had time when returning the car, took a picture of the 'damage' and appealed both to Avis and my credit card company. The credit card company denied Avis' claim as frivolous.

So these experiences can happen with any company. I ALWAYS go over cars now with a fine tooth comb before leaving the rental lot and have any company, even top tier ones, mark down any slight damage that I see.

The explanation about getting a replacement car with a top tier company in case of a breakdown is probably valid, unless you are really off the beaten path anyway then no company would be "close."