I have intimate experience with both the Emotiva XPR-1 and XPA-1 (Gen 1) as well as XPA-1L (Class A 30 watts).
I took a quick look at the Levison 333.5 amps and I will say that the Levisons will contain components (caps, resistors, etc.) that are far superior that anything Emotiva will have. That being said, Levinson will have its own sonic signature that you may or may not like. The Emotiva products are awesome in the fact that the company charter is to take a set of low cost components and design the best product they can with them, then take out the dealer markup and sell at a very low price (for what you are getting). It may or may not outperform other amps and combinations.
The XPR-1 is an excellent amp for the money. That being said, it is a tad soft and just a tad cold out of the box. Replacing the stock fuses with Isoclean fuses tightened up the sound and made the transient responses quicker. It also warmed up the sound as well. Please be aware that the XPR fuse holders are not designed well. They are very tightly conformed to 31.8mm length and they are not very strong in holding the fuse. The edges of the fuses may have to be sanded/grinded a bit because 32mm length is too long and will not fit properly. If you have the DIY skills for this, the XPR is an awesome choice. I do not know how it compares to Levinson, though.
The XPA-1 is also a great amp. It doesn't have the softness issue of the XPR, but it can be a bit bright. Fuse replacements fix this as well (they use 20mm fuses, so sizing is not an issue).
The XPA-1L and XPA-1 Gen 2 with the Class A switch fix a lot of problems that come with the solid-stateness of these amps (especially if your source/preamp equipment is very solid-state sounding). It makes the overall sound more smooth and natural. However, I would not recommend buying these if you are not planning to run them in Class A mode. The Emotiva amps do not have a proper circuit for the non-Class A mode and there is crossover distortion that may come across as being bright in the highs. The smaller XPA-1L is nice in Class A mode, but does not have the brute force of the higher power amps and you will not get as much bass / midbass strength.
