Need insight on these amps

I just sold my power amp and a few other components. Looking to buy a first class amplifier for my Platinum Audio Solos which are a difficult load but I like the way they sound. Right now I see the following amps available in different websites:
1) Krell FPB 300
2) ARC D-400
3) ARC 300.2

I would like to hear from anyone who have heard these amps in the past what is their opinion on them. I'll be using a tube preamplifier. I'm also open to suggestions on amps that retain their value over time. Thanks in advance for your time.
Hi audiogabby,
The VK-500 I had was opted out to the max as well. The difference between the 200 and 500 was extraordinary but so was the price. And yes, my 500 came from the early 2000s and I have to wonder if Viktor's stuff is still the same. I certainly understand about the ability not to be able to demo. It seems with the advent of the internet there is a lot of gear for sale but not much ability to "try before you buy". What type of load does the speaker you wish to buy present? The reason I had the Krell was to drive a pair of Apogee Stages way back in the day. Interesting story is that I actually drove the Stages with some tube amps. Jason Bloom the former owner of Apogee learned of this and he actually called me to tell me it could not be done. I played for him over the phone the amps playing the speakers (no Youtube or text messaging in those days) and he was astonished. He had promised to see this the next time he was in Seattle but sadly he passed before that happened. The reason for the story is this: some tube amps can drive some difficult loads; it is just not all that common but possible just in case you want to stay or go with tubes. Another choice might be some older McCormack amps, the DNA series. I used a pair of their monoblocks once and while not in the same league as the BAT or my large tube amps, they were pretty good once Steve "hot-rodded" them.
Thanks for the patience with my long answer.

My last amp was a good amp but lacked transparency and therefore i felt the soundstage was not that well defined. I thought also about getting more power. They didn't feel like they were that powerful driving the Solos.
@audiogabby , sorry I doubt an amplifier is going to fix your problem with those speakers (based on Stereophile review, good bass, but too polite in other areas). You should consider selling the speakers as well, and purchase an amp and speaker combo that's had good reviews.
@golfnutz  So your assessment of the OP's "problem" and advice to the OP is based solely on your referencing someone else's review?  None of this is based on your first-hand experience?  And your advice is simply "sell everything and buy something else with good reviews"???  No one needs input from a message board for that.
The Solos are tough but they are good speakers. I paired them with a few amps in the past that have brought up some good qualities in them. The thing is those good qualities were at the expense of something else. With the right amp these speakers are keepers.