Is an isolation transformer better than a power conditioner?

Well, you can pay for a $189.00 or so for a Tripplight isolation transformer.It has 1800w capability and regulates down to 85v to 145v to 120v.  It also has RFI suppression. Filters spikes and noise.  I use a Furman power strip in front of that which also has RFI filtering and a 145V clamp circuit which shuts down power at that Threshold to protect the isolation transformer. Probably under $300 total.  My primaluna is silent with this turned up loud. No hum no hiss. Or you can pay thousands if that makes you feel better. I dare to  compare.  $$$$$$$ does not always add up to better sound. 

FWIW. Balanced AC is simply 120 Volts that has been split evenly across two AC mains. One phase is +60V while the other is -60V. The mains are always 180 degrees out of phase across the load and therefore sum to 120 Volts, the same voltage and frequency for which equipment power supplies were designed... When the incoming 120 volts is split into 2 60 volt lines 1/2 the powerline noise/distortion is on each 60 volt leg. When the legs rejoin, out of phase -to make 120 volts- the 'mirror image' noise/distortions of each leg cancel each other leaving dramatically cleaner power. This is not rocket science or magic; and it works. Complementary products can certainly improve on this if wisely chosen. Experiment and have fun. 

^^^^ +1, @ptss 

I'd go with one of the ultra low capacitance Ultra/Extreme/High Isolation transformers from the likes of Topaz/MGE/ECA/Xentek/Elgar/Daitron. A lot of them come with balanced output (and it not they can be wired that way). They may also come with a film capacitor on the outlet output. The best of the lot will have .0005, .0001, or even .00001 pico farad capacitance and -150 dB+ and -65+ common and normal mode noise reduction respectively. Then have a nice passive power strip plugged into it to plug in all your components.

The BPT 10.5 and 3.5 units also seem to be a real bang for your buck with a giant Plitron toroid, and extra shielding, premium wiring and outlets, capacitors on the outlets, and other goodies.

As for a UPS, they are a great option, go for an on-line (not like internet online) double conversion unit from the likes of Eaton, Liebert, APS, Cyberpower, MGE, or SurgeX. In my research Liebert has the lowest THD and highest Power Factor capabilities. I cannot speak for other noise reduction capabilities. I know Furman, Monster (in the past), and PS Audio make or have made UPS' but I am not sure if any of those are on-line units.

There's a better option of ac power source/power supply generators that are better then UPS' or audiophile regenerator units. They are sine wave ac generators where you can choose the frequency and voltage output, but they rarely have a built in outlet, and cost a lot for high VA/Watts output. You can find quite a few with 900 VA output with a single duplex, not many with output over 1,000 VA. I just saw a couple of Titan MAC 01 units on eBay with 1,000 VA output.

There's also Topaz and MGE line conditioner/power conditioner + voltage regulators. They have a large transformer in them that is saturated by a large capacitor but aren't just isolation transformers.