Hey.
Been doing race tracks to ETH back and forth like crazy for the past year or so.
First - SDV vs. TLV
SDV - Very easy access from the TLV area, If you are looking for a bargain and aren't carrying too much luggage, you can park your car in the free Reading Parking and walk to the airport in about 10 minutes. The airport itself its chronically understaffed so security takes a while, however they always made sure to get ppl to their planes in time in my experience. The airport offers amazing views of the Gush Dan area, which I will happily admit to admiring even after doing this route for dozens of times. However, Public Transport is terrible and if you need to get there or away from there during the Rush Hour, you're almost definitely going to spend your precious time stuck in traffic. Baggage claim times can be so-so, especially late in the evening.
TLV - Domestic Terminal 1 is ok. The best public transport option is to take the bus to Zomet El Al and walk from there, as arriving via train and shuttling from T3 is a colossal waste of time and energy in my mind. No duty free or food\beverage options to speak of, but flights tend to be just a bit cheaper than from SDV
Now about the airlines:
Israir - In my experience, crews are nice and attentive. They operate ATR 72's out of SDV and A320s out of TLV. Both are okay, however the flight takes around 20 to 25 minutes more on the ATR, which might not seem that critical but does infact matter if you plan on doing this on a regular basis. In my experience, Israir has less flights but tends to be a bit cheaper than Arkia. Water and a small snack is served during the flight.
Arkia - Service is ok, not much more than that. Ex-SDV they operate ERJs which are about 20 minutes faster than the ATR Israir uses. The aircraft is comfortable and stable even during severe weather. Water and snacks are served during the flight. The flights are usually a bit more expensive (Although there are bargains available early in the morning and late in the evening which are actually pretty amazing if you travel for business.) but there is more availability because of increased frequency and more seats in every plane. Ex-TLV, they operate a mix of ERJs and 753. Flying the 753 to ETH is fun if you're an aviation geek, however the plane is less comfortable and tends to be late because boarding takes more time.They used to operate an ATR too but as far as I know they (finally) got rid of it.
Both companies offer significant discounts when purchasing a ticket pack (Called Tick-Tack with Arkia) and another discount on top of that for Eilat residents. The picture will obviously shift as soon as Ramon Airport becomes operational and transit times increase dramatically (around 25 minutes from the city centre without traffic jams). Right now its really awesome to be able to walk to the airport in SDV. get off the plane in ETH and walk to most places in the city.
A bit OT, but here's hoping that when Ramon Airport opens, RYR will enter the game and drive prices down, I've been flying them a lot lately - if they can do Paphos which is 40 minutes out of TLV, there is no reason they can't operate a flight from TLV to Eilat successfully.